I seem to recall a big spy case in the 80s that was messed up by RAFP. The 'Mata Hari' case as it was known. Said suspect was forced into a confession by friendly SIB.
Learning from that mistake, they repeated it shortly after, only with eight suspects. They were also found not guilty for exactly the same reason.
That trial went on for months in the Old Bailey. Must have cost a fortune.
BTW, I notice that nobody's started a thread saying 'Why we all love the RAFP'.....