Which brewery marketed the first canned beer in the UK, and when?

According to their advertising and some other stuff on the web that has evidently been cribbed from the same source, it was Felinfoel Brewery Company of Llanelli in December 1935.

Llanelly at the time.... Properly on the market in 1936, but first batches in December 1935. Now, for a bonus (Golden Leek?): why were Felinfoel and their local rivals so keen to put beer in cans?

There was pressure from the local tinplate manufacturers of South Wales, who had been hit very hard by the depression, to replicate the success that brewers had had in the US over the preceding year selling beer in cans. Although more expensive to produce than bottled beer, canned beer had turned out to be much cheaper and easier to ship and store.