Most certainly the first English scientist ever was Adelard of Bath. He championed Islamic learning and was the most `Arabist' of all scientists. He and Daniel of Morley were instrumental in the transfer of scientific knowledge from Islamic civilisation to England and beyond.
Summarised extracts from a full article:
The Impact of Islamic Science and Learning on England by Salah Zaimeche
Adelard of Bath and Daniel of Morley are the two most influential English scientists, not just because they were amongst the very first, but also because they brought in some fundamental elements into English, and Western, intellectual life.
Most certainly the first English scientist ever was Adelard of Bath. He could be said to have championed Islamic learning more than any other early scientist, being the most `Arabist' of all scientists. He was born in Bath, studied at Tours (France) and taught at Laon (France). After leaving Laon he spent seven years in study and travel, and can be traced in Cicilia and Syria. He might have visited Spain and Sicily before 1116 and probably before 1109 and was in Palestine by 1115. By 1126 he was back in the West, busy making the astronomy and geometry of the Muslims available to the Western Christian world.
Adelard's most important contributions were in the field of mathematics. Early in life, before he travelled to Syria and Palestine, he wrote a treatise on the abacus (Regule abaci). Later, in 1126, he translated from Arabic into Latin the astronomical tables of al-Khwarizmi, revised by Maslama ibn Ahmad al-Majriti. They included tables of sines. Thus was Muslim trigonometry, and more specifically the sine and tangent functions, introduced into the Western Christian world.
At the time he was compiling his natural questions, Sarton informs, Adelard also wrote a treatise on falconry, the earliest Latin treatise of its kind which has come down to us. It shows no trace of Arabic influence. Thus, Adelard must have written it rather early or else he did not hear of eastern knowledge on the subject, but the matter, Sarton notes, requires further investigation. He was also, Sarton tells, in all probability the "Magister A" who translated al-Khwarizmi's mathematical treatise (Liber ysagogarum Alchorismi). Thus, Adelard was an abacist at the beginning of his career and later became an algorist, the earliest (or one of the earliest) of them. Just like Petrus Alphonsi, Adelard became associated with the court of Henry I. Both men were important in the transmission of Islamic science in both court and kingdom as well as much of the West. Both worked on the Zij of al Khwarizmi. Whether this was done individually, or in cooperation, cannot be proved, but it might have happened after Adelard returned from his seven year travels.
Adelard's travels had begun years before, soon after his formal training in the Latin schools. He embarked on a journey, which took him to Magna Graecia and the principality of Antioch. It is this seven year journey which he describes, famously, as his quest for the studia Arabum (the studies of the Arabs), which he contrasts to the Gallica studia (French studies).
`Arab' studies based on reason rather than authority.
Cochrane charts his travels, telling that it is probable that Adelard made his way to Syria via southern Italy, Sicily and Greece. In De eodem, which he dedicated to the Bishop of Syracuse, he mentions both Greece and Salerno, whilst in his famed Questiones he describes being shaken by an earthquake as he crosses a bridge at Mamistra (modern Misis) near Adana on the way to Antioch. He speaks of the bridge itself and of the whole region as shaking violently with the movement of the earth. Adelard's mentioning of the earthquake, Cochrane notes, is very useful in establishing a date for his journey. The earthquake took place in 1114 and affected Anatolia, and caused great damage to Antioch, which is one hundred miles from Misis, and as far away as Edessa. It was the time of the first crusade, when the Franks were under serious threat from forces being raised against them by the Seljuk Sultan Mohammed. Roger of Salerno was Prince of Antioch and personally supervised repairs to the fortifications.Cochrane then highlights some very interesting points on how Adelard witnessed the Seljuk fixing bridges damaged by the earthquake and how their techniques were soon after to be seen in England.
Adelard's masterpiece is a collection of Natural Questions, which gave him the opportunity to publish Islamic knowledge on a variety of subjects. It is the result of his seven years of travel amongst the Muslims in the east, as mentioned above. When Adelard left Laon, he advised his `nephew' and his other pupils to remain there and learn all they could of philosophy as it was taught in northern France. He would travel and study with the `Arabs' and on his return they would compare notes. Quaestiones naturales is the resulting essay. The Quaestiones Naturals is in 76 chapters, each dealing with a scientific question, to explain the new knowledge which he had acquired from `his Arabs.' Quaestiones Naturales is in the form of a dialogue between the author, who has just returned from his journeys and is still full of the new impressions of Muslim science thus gained and his fictional nephew, who has had a scholastic education in France.Adelard could no longer endure the prejudice against modern science which in his time was synonymous with Islamic scholarship, especially after he had spent those seven years in study and travel in order `to investigate the learning of the Arabs as best as he could.' Looking at Adelard's brief outline in Haskins and his dealing with matters of plants, natural life, and geological questions, one is struck by the close resemblance they have with the works of Muslim botanists such as Al-Dinawari and Muslim geographers and geologists such as Al-Biruni, in particular. This comparative work has not been done, and to this day, Adelard's quaestiones, except for some brief extracts here and there, are only widely available in German, yet another crucial work the English speaking world is deprived of.
Adelard also brought back a unique enthusiasm for Arabum studia. Adelard declared that from his Muslim teachers he had learned to put reason above authority in the matter of natural knowledge since in fact the Ancients, who now possessed the authority, had gained it only by using their own reason. He says,
"From the Arab masters I have learned one thing, led by reason, while you are caught by the image of authority, and led by another halter. For what is an authority to be called, but a halter? As the brute beasts, indeed, are led anywhere by the halter, and have no idea by what they are led or why, but only follow the rope that holds them, so the authority of writers leads not a few of you into danger, tied and bound by brutish credulity."
Thus, Adelard had triggered a completely new approach unknown then, the use of reason rather than authority, his line the very foundation of modern scientific thinking. His works `mark a significant stage in the history of ideas,'. Such eagerness and faith in human reason: `If reason be not the universal arbiter, it is given to each of us in vain.'
It seems that English-based scholars (i.e. the older generations), as a rule, acknowledged openly the place and influence of Islamic science. The same eagerness is found in this regard in Daniel of Morley as in Adelard of Bath. Daniel of Morley proceeded to Cordova to learn mathematics and astronomy, published the fruits of his studies, and lectured at Oxford. His passion for Islamic learning is well caught in his dedication of his Philosophia to John of Oxford (Bishop of Norwich from 1175 to 1200), of which lengthy extracts are taken from Burnett:
`When, some time ago, I went away to study, I stopped a while in Paris. There, I saw asses rather than men occupying the chairs and pretending to be very important. They had desks in front of them heaving under the weight of two or three immovable tomes, painting Roman Law in golden letters. With leaden styluses in their hands they inserted asterisks and obeluses here and there with a grave and reverent air. But because they did not know anything, they were no better than marble statues: by their silence alone they wished to seem wise, and as soon as they tried to say anything, I found them completely unable to express a word. When I discovered things were like this, I did not want to get infected by similar petrification.... But when I heard that the doctrine of the Arabs, which is devoted entirely to the quadrivium, was all the fashion in Toledo in those days, I hurried there as quickly as I could...'
Daniel pursues that he was begged to return to England from Spain by his friends, but was `disappointed' with what he found. Asked by his friend the bishop about `the wonderful things in Toledo,' the teaching there, and the movements of the celestial bodies, Daniel submitted a treatise for his scrutiny. Its first book was about the lower part of the universe, its second about the higher. He then begs the reader that
`he should not despise the simple and clear opinions of the Arabs, but should note that Latin philosophers make heavy weather of these subjects quite unnecessarily and, through their ignorance, have put figments of their imagination veiled in obscure language, so that their unsteady floundering in this subject might be covered by a blanket of unintelligibility.'
Already in 1180, Daniel of Morley had returned to England convinced with Albu Al Ma'ashar (Albumasar) that he who condemns astronomy destroys science. Like Adelard, he emphatically relies on the Muslims against the antiquated authority of ancient Christian authors. Abu Ma'ashar was, in the words of Alain de Lille, the undisputed master of stellar science.
The image shown is from http://special.lib.gla.ac.uk/exhibns/month/june2001.html (is a copy of Euclid's Elements translated from Arabic into Latin by Adelard of Bath)
-L. Cochrane: Adelard of Bath, British Museum press, 1994.
-C. Burnett: Adelard of Bath, Warburg, London, 1987.
-B.G. Dickey: Adelard of Bath, unpublished Thesis, University of Toronto, 1982.
 C.H. Haskins: Studies; op cit;. Pp 33-4.
G. Sarton; Introduction; vol 2; p. 167.
G. Sarton: introduction; 2; p. 168.
G. Sarton; Introduction; vol 2; p. 167.
 L. Cochrane: Adelard of Bath; op cit; p.42:
C. Burnett: The Introduction; op cit; p. 25.
 L.Cochrane: Adelard; op cit; p. 33.
 L.Cochrane: p. 33.
 L.Cochrane: Adelard; op cit; pp. 34-5 and fwd.
 Quaestiones naturales edt Muller
 E.J. Dijksterhuis: The Mechanisation of the World Picture; Oxford at the Claredon Press; 1961; p.118.
 D.Metlitzki: The Matter of Araby; op cit; p.13.
 see Haskins' summary on The Quaestiones in C.H. Haskins: Studies, op cit pp 36-8.
 D.Metlitzki: The Matter of Araby; op cit; Chapter 2: p.13.
 E.J. Dijksterhuis: The Mechanisation; op cit; pp.116-7.
 N. Daniel: The Arabs and Mediaeval Europe; p. 265-6. in Questiones, ch vi, on why man must use reason with which he is endowed.
 L. Cochrane, Adelard of bath, op cit, p. 1.
 G.Wiet V. Elisseeff; P. Wolff; and J. Naudu: History of Mankind; Vol 3: The Great medieval Civilisations; Trsltd from the French; George Allen &Unwin Ltd; UNESCO; 1975. p.465.
R. Briffault: The Making of Humanity, George Allen and Unwin Ltd, London 1928. p.199
In C. Burnett: The Introduction; op cit; pp.61-2.
 Daniel of Morley, Philosophia, ed. G. Maurach, pp 204-55; in C. Burnett: The Introduction of Arabic learning, op cit, p. 62.
 Daniels Von Morley Liber de naturis inferiorum et superiorum; ed Sudhoff; p. 32; in D. Metlitzki: The matter; op cit; p. 60.
A de Lille in D. Metzliki: The matter; op cit; p. 60.