My younger brother was caught in the 1991 slump as a BA Prestwick CEP. They were told "if you want to wait your turn, we will take you on in strict graduation order". He did and they did. However, while he was on the list they took over BCal and Dan Air - leading to a huge influx of more senior, laid off pilots who slotted into the pool above him (I believe he was holding down a number greater than 500 at one point!).
BA had first call on all CEPs for 12months - after that they were free agents. BA also said that they would consider on merit any application by a CEP to leave the pool before the 12 months was up if they were offered a job - and a great many did. My brother stuck with it, got a job in BA customer services at LHR in the meantime to gain pension/staff travel rights, and waited his turn. After 3 years on 737 at LGW he is now into his 3rd year on 777 at LHR/LGW. He believes it was worth it.
BA were true to their word - they gave all the CEPs jobs in turn although they were unlucky to get the DAN/BCal guys drop in on top of them.
My brother has been told that BA will need to replace over 200 pilots next year - even with the reduction in capacity. BA are not finding it easy to recruit from other airlines these days - the pay and conditions do not have much advantage over the likes of easyJet!!!! The BA CEPs here (who are behind quite a number of others in the pool) have been told ABSOLUTE WORST CASE is 2 years.
In my opinion - don't give up hope - you will get a job and I believe it will be sooner rather than later (BA will be recruiting once Stelios has bought you out, closed Waterside, sacked thousands of bean counters, expanded the route network and painted the jets orange!).