c.602. Augustine meets the British bishops (?)
Two meetings between Augustine and the British bishops are described by Bede (HE, ii.2). The meetings are not dated, but since one of the things to which the British object is accepting Augustine as their archbishop, they would probably have taken place shortly after the Pope gave Augustine that authority in a letter of 601.
The first meeting, arranged with King Æthelberht's help, took place at "Augustine's Oak" (unidentified, but said to be on the borders of the Hwicce and the West Saxons). Augustine argued that the British bishops and teachers should conform more closely to catholic doctrine and help to evangelise the English. When argument proved unavailing, the two sides went on to "trial by miracle": a blind Englishman was brought, and where British prayers proved unavailing, Augustine's prayers restored the man's sight. The Britons then confessed that Augustine was right, but that they could not abandon their former beliefs without the consent of their people. A second and larger meeting was arranged.
Before the second meeting, the British sought the advice of a holy hermit, as to whether they should forsake their traditions and follow Augustine. The hermit replied that if Augustine showed himself to be meek and lowly of heart, then he was a man of God and deserved to be followed: if, on the contrary, he was harsh and proud, he was not from God. The hermit further suggested that if, when the British came to meet Augustine, he rose at their approach, that would demonstrate his humility. Most unfortunately, Augustine remained seated when the British arrived, and so no agreement was reached. According to Bede, Augustine then threatened the British that if they refused to accept peace from their brethren, they would suffer war from their enemies, and if they would not preach the way of life to the English, they would be killed by them. Bede saw the fulfillment of this prophecy in the battle of Chester of c.613, in which the prayers of British monks proved ineffective against the wrath of Æthelfrith of Northumbria.
So far the story. With its allegorical miracle (for healing the blind Englishman, read converting him) and soon-fulfilled prophecy (easy enough in hindsight), it reads more like Bede's ideal of how Augustine might have confounded the British than an accurate account of historical events c.602. That there were meetings between Augustine and the British bishops is very likely. That these did not result in a joint plan to convert the English is plausible, and would explain Bede's hostility to the British church a hundred years later.
It should be emphasized though that Bede's information is incomplete, and such evidence as we can gather suggests that while the British church may not have played a top-heavy institutional role, the British were probably much more involved in the conversion of the English than Bede was prepared to admit. Sims-Williams (at pp.75-9) has plausibly suggested that the Hwicce and Magonsætan, English groups on the Welsh borders who are already Christian when Bede first mentions them, were converted unobtrusively by their British neighbours. This fits with Meens's recent demonstration that Augustine's eighth question to the Pope in 601 (reported by Bede at HE, i.27) closely reflects concerns of the contemporary British church, which implies that Augustine sometimes had to deal with English who had already been exposed to (and perhaps converted by) the doctrines of the British Christians.
J. Campbell, "Observations on the Conversion of England", reprinted in his Essays in Anglo-Saxon History (London, 1986), pp.69-84, at pp.71-3
R. Meens, "A background to Augustine's mission to Anglo-Saxon England", in Anglo-Saxon England, 23 (1994), pp.5-17
P. Sims-Williams, Religion and Literature in Western England, 600-800 (Cambridge: 1990)