The best known is Bass' King's Ale. This has even made it onto the Antiques Roadshow where it was identified as King's Ale, and it was said that the bottle dated from 1902, that the beer had been brewed by King Edward VII on a visit to Bass at Burton and that the bottle was worth £250. They were quite right, it was a bottle of Bass' King's Ale - but that is the only bit that was correct, the rest is garbage.
On his visit to the brewery in 1902 Edward VII turned a valve which allowed hot water to flow and started the mashing process for the beer; I will leave you to decide whether you think that that could be accurately described as brewing the beer. Once fermentation was complete the beer was not bottled straight away. It was stored in casks under controlled condition for several years before bottling started. The earliest date at which bottling may have occurred is 1905 but it continued over an extended period. A number of other companies were allowed to bottle it although they had to use the name "Royal Ale", "King's Ale" only being used for Bass bottlings.
To create even more confusion Bass kept a large supply of original bottles, labels and corks. These have been used to relabel and re-bottle the beer over a very long period. When Bass at Burton celebrated their bi-centennary in 1977, a quantity of the beer was re-bottled with original labels and corks. Everyone who had worked at the brewery for 10 years or more received a bottle, and there are large numbers of bottles around. The price you can expect to pay for a bottle is nothing like the Antiques Roadshow suggestion of £250. A range of £10 to £18 is often quoted but about 3 years ago I paid £8 for an early bottling and at a recent collectors meeting a number of bottles changed hands for £5 each.
A similar beer, Prince's Ale, was produced as the result of a visit to the Bass Brewery by Edward, Prince of Wales, in 1929. It was still being sold in pubs, or at least in some of the posher London bars, for drinking in 1945. I paid £25 for a bottle last year, which seems to be regarded as a little on the high side, but is just within the quoted price range for the beer.
The oldest of the three traditional Bass' corkers, Ratcliffe Ale, was brewed in 1869 to mark the birth of Robert Ratcliffe, a son of one of the directors of the company. It was originally intended to be laid down to be drunk for his 21st birthday celebrations. This is a rarer bottle than King's Ale and a price of around £30 is often quoted for it. However at a recent collectors meeting I managed to pick up a pint bottle for £10 and a quart for £15 and these were not exceptionally low prices.
A bottle of Ratcliffe Ale was opened on 16th December 1969, the 100th anniversary of the brew, and was generally considered to have kept well. Thirty years on and I have recently had the opportunity to taste some. (Not from one of my bottles!) While there were distinct acetic undertones, it was still a rich, fruity beer and quite drinkable. It must have been of some strength to survive so long.
And finally, for a laugh, in an antiques centre not too far from Cambridge one stall has a number of Jubilee and Royal Wedding beers from national and large regional brewers marked at £10 each. Expect to pay around 50p for the same bottles at specialist breweriana events.