By Paul Majendie

LONDON, Jun 5 (Reuters) Britain should have its own national day to reinforce a sense of Britishness and there should be tougher rules to make immigrants ''earn their citizenship'', two government ministers said today.

''We need a stronger sense of why we live in a common place and have a shared future,'' Immigration Minister Liam Byrne and Communities Secretary Ruth Kelly said in a political pamphlet written to provoke debate on the highly sensitive issue.

Multicultural Britain has re-assessed its attitude to racial and religious minorities since suicide bombings in July 2005, when four British Islamists killed 52 people on London's transport system.

A Channel Four Television poll yesterday showed that one quarter of Britain's 1.8 million Muslims believed government agents staged the July 2005 bombings, pointing to a sense of isolation among minorities living in divided communities.

Immigration is a burning topic in a country whose population rose by 500 a day in 2005, the number of new immigrants far outstripping the total leaving the country.

Almost five million of the 60 million people living in Britain were born abroad. The Treasury estimates immigration adds about half a percentage point a year to long-term economic growth.

The ministers proposed an ''earned citizenship'' points system under which migrants would be allowed to become British citizens only if they demonstrated good behaviour and a readiness to integrate.

They would have to accrue credits by undertaking civic voluntary work, living in a law-abiding way, passing English language tests and showing a knowledge of British culture.

''This form of points system would be the basis of a clearer relationship betweem the citizen and the state,'' the ministers said.

Countries like France, the United States and Australia have a national day to underline a sense of patriotism and ''We have to recognise what is distinctive about Britishness,'' Kelly said.

Traditionally reserved Britons have often been reluctant to trumpet their Britishness and Kelly said she and Byrne were not suggesting people should ''stand in their front gardens and salute the Union Jack'' on a British national day.

But Kelly, whose views on the subject are shared by prime-minister-in-waiting Gordon Brown, told BBC Radio on Tuesday: ''The point of it would be to celebrate the contribution that we all make to society.'' REUTERS SYU HT1450