Up to 180,000 people a year could be paid resettlement grants of £50,000 to leave "overcrowded" Britain under the BNP's immigration policy, the party's leader Nick Griffin said today.
He stressed this would be a voluntary programme for those who were not defined as White British.
Mr Griffin also said the country's doors would be shut, except to those immigrants whose entry would suit the UK, such as physicists with specialist skills.
"We mean that the doors are going to be shut, because Britain's full. We are the most overcrowded country in Europe," Mr Griffin told BBC Radio 4's Today programme.
"If you are talking about Polish plumbers or Afghan refugees, the doors are going to be shut, because Britain is full."
He went on: "The door is shut to any significant numbers whatsoever, from anywhere. It's open where it suits Britain and suits the British people. That's fair enough."
He gave the example of a Japanese physicist needed to help with the UK's nuclear programme as somebody who could be admitted under the party's plans.
Asked if he was content that his immigration policy would mean tearing up international treaties, Mr Griffin replied: "Absolutely. They don't suit Britain and the British people. It's a political elite project, all this internationalism."
On repatriation, Mr Griffin said: "We are saying that we would give resettlement grants and this is purely voluntary.
"We are looking probably at about £50,000 per person."
Asked how many people would leave, he replied: "180,000 people a year, if they want to leave this drastically overcrowded country."