The island is named after the Phillimore family who were formerly the owners of Shiplake House, now Shiplake College. Apparently now known as Buck Ait (though this is also a name given to the small islands above Hallsmead Ait)

Phillimore's Island, Henry Taunt

1881: George Leslie, "Our River" -

There is an island just above Shiplake weir;  the best punting course is to make for this island, passing on the Berkshire side, then cut across to the Oxford side on which the tow-path is, making as straight a course as you can.  I mention this, as the other side by the tow-path is longer, and the ground very muddy.  But the punting is not good anywhere until you get above the island, the water being all very deep.

[ George Leslie was used to boats being towed - which is something we never see today - the towpaths are certainly far too overgrown for one thing, and the traditions of how to do it, and how to pass another boat, have been lost ] -

For those towing, there is near here a very awkward place, like many others of the same description on the river, wherever a sharp bend occurs, and the tow-path runs a good way in shore, with a large swampy piece of sedges and rushes between it and the river edge;  what usually happens is, that the tracker walks along until he has passed these rushes, and finds himself suddenly brought to a standstill by the boat having become jammed into the soft bank.  Those in the boat endeavour to push off, but each time they do so, the tracker pulls them in again.  The proper way to pass these bits, is for the tracker to stop when he comes to the commencement of the objectionable piece, and for the people in the boat to commence at once to row or shove, the tracker walking slowly along, keeping level with the boat, and holding the line slack.

Twyford & District Fishing Club -

A nice stretch of the river that starts at the downstream end of Buck Ait and runs past Hallsmead Ait and The Lynch down to Phillimores Island and the mouth of Borough Marsh Stream, a distance of approximately three quarters of a mile. Good catches of bream and skimmers can be had from pegs 1 to 7, with chub being the main quarry on pegs 8 – 21 facing Hallsmead Ait. Do not ignore the inside line on these pegs, as there are plenty of fish to be had on the pole or waggler, especially as the roach start to show in late summer early autumn. Pegs 21 to 25 are on one of the wider stretches, and most fish come from the inside, that is if you disregard the barbel that can be caught from the middle “The Platforms” pegs 25 – 30. These pegs are opposite The Lynch, and as before chub can be caught against the island. Fish can be caught in the inside and from the middle of the river, but this area can be fickle. However, come the winter, this is the area for the pike. Open 16th June to 14th March inclusive.