Rail union leader Bob Crow had what he called a "close shave" after inadvertently trying to enter parliament with a sword.
No uprising planned at present
The RMT boss says he forgot that the 10-inch weapon was in his bag, which also contained the Millwall fan's football kit.
After the incident the left-winger joked to BBC News Online that if he had been planning to lead an uprising he would have given advance notice.
Mr Crow told BBC News Online: "I was given this ornamental sword by the South Korean rail union.
"It was in my bag but I forgot to take it out when I was shoving in my football kit.
"Anyway I got down to the House of Commons for a meeting and the security people - one of whom I know - found the sword."
He added: "I've apologised to the authorities about what obviously was a bit of a close shave and I should point out I don't normally carry a weapon.
"It couldn't have been that serious though because they gave me the sword back."
Security at the Parliament has been at a high level for years but has been significantly stepped up in the wake of the 11 September terror attack.
Now 400 police officers and security guards patrol Parliament.
Many of the police carry sidearms and submachine guns.