Campaigners dressed as George Osborne, Ed Balls and Danny Alexander have staged an anti-tax dodging protest outside Parliament.
Members of Oxfam's tax dodging campaign posed in rubber masks and red budget boxes inside a glass dome blowing fake bank notes everywhere.
The stunt represented the amount of money the Treasury lost each year due to tax dodging, they said.
The protest called on the main political parties to pledge a new Bill to stop large companies exploiting tax loopholes.
A spokesman for Oxfam said the practice was "immoral".
Nick Bryer, head of campaigns for Oxfam, said: "Corporate tax dodging is on the increase and 85% of the UK have accepted that even if it's legal, it's immoral and it is not fair. Everyone should pay their fair share.
"We believe a tax dodging bill would save the Treasury £3.6 billion, and that poorer countries could save billions as well.
"Any sensible person who looks at the tax laws will say they are overcomplicated and need more transparency. They can see it's of no benefit to society and should be illegal.
"This is about transparency and it's not just about the UK, it's about poorer countries too."