But he was best known for his connection to the Brink's-Mat heist, for which he was tried in 1987. He was said to have melted down bullion from the robbery in his back garden, but he denied knowing the bullion was stolen and was acquitted.
The robbery was carried out by a gang of six, who had expected to find 3 million in cash but instead discovered three tonnes of gold in the warehouse owned by an American security company.
Only three men - Micky McAvoy, Brian Robinson and his brother-in-law Anthony Black, a security guard at the warehouse - were ever convicted of carrying out the robbery.
Because the gang had no expertise in handling gold, they had to recruit other underworld figures to help them dispose of the metal and launder their money.
Gangsters connected with the robbery fell out with each other and violence followed. Around half of the stolen gold remains unaccounted for.
Palmer had been charged with fraud, firearm possession and money laundering after an eight-year timeshare con investigation in Tenerife, where he had his second home.
Days before his death he had been told he could be facing a 15-year prison sentence.
7 deaths linked to the Heathrow heist
1. Nick Whiting, who was accused by some gang members of being an informant, was the first to be killed, in 1990, when he was stabbed nine times and shot twice.
2.The same year Charlie Wilson, one of the Great Train Robbers, who had been hired to launder some of the proceeds of Brink's-MAT, was shot dead on his doorstep in Marbella.
3.Donald Urquhart, a money launderer, was found shot dead in 1995.
4. The following year Keith Hedley, another suspected money launderer linked to the raid, was shot and killed by three men on his yacht off Corfu.
5. Two years later Solly Nahome, a Hatton Garden jeweller said to have handled the stolen gold, was found dead outside his home in Finchley with four bullets in his head.
6. Then in 2001 Brian Perry, who served a jail sentence for handling the gold, was shot in the head.
7. George Francis, said to have been another member of the gang, was also shot dead the same year.