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.
All the special coins will be available in collectable versions and the three lower value coins will also be available from banks and post offices later in 2007.