A £2 coin will be issued next year to mark the 300th anniversary of the Act of Union between England and Scotland, Chancellor Gordon Brown has said.
There will also be a £2 coin to mark 200 years since the abolition of the slave trade, he told MPs.
And a collectable crown piece worth £5 will mark the Queen and Prince Philip's diamond wedding anniversary.
"Collector versions of all these coins will be released at a premium above face value," Mr Brown said.
A statement issued by Mr Brown, who is Scottish and widely tipped to become prime minister next year, said the Queen had approved his recommendation that a coin be issued to mark the unification of England and Scotland into Great Britain in 1707.
Mr Brown also said there would be a special 50p coin to commemorate the centenary of the Scouting movement.