A fresh drive to strengthen ministerial support for British entry to the euro is to be made by the Europe minister, Denis MacShane, who is circulating copies to all ministers of the fiercely pro-euro speech made by Tony Blair in Tokyo last month.

The prime minister's speech had been intended to mark a clear new phase in the government's slow march towards the euro, but its impact was heavily overshadowed by the death of the government weapons expert David Kelly.

Mr MacShane said yesterday: "After the chancellor and prime minister's statements of June 9, it is time to move from a period of analysis and to explain why it is in Britain's long-term interest to be prominent members of the European Union and members of the euro."

Mr Blair has insisted he has changed gear to a more pro-euro position after the cabinet's agreed June 9 statement that Britain was not yet ready to join the euro since it had still not met all five economic tests set by the Treasury.

In the Tokyo speech, Mr Blair said the economic benefits of membership were in the long-term equivalent to more than current UK spending on education and pensions.

He also suggested that Britain need not delay entry until the rest of Europe has completed reforms designed to make their labour markets more flexible. Indeed, he argued, Britain might benefit from joining the euro at a time when Britain had a more flexible labour force.

"We could enjoy a period of superior growth because of our superior flexibility in the UK, and that clearly is not the greatest disaster that can befall a nation," he said.

The Treasury has tended to emphasise the need for greater labour market flexibility on the continent as a precondition for British entry.

Mr Blair also proposed that reforms to make Britain more convergent with EU economies did not need to be completed before he would recommend entry.

"While it may be reasonably argued that some structural matters can only adjust over a period of years, that is to misunderstand the nature of the tests themselves," the prime minister said.

"We are not looking for completion of the impact of reform in all areas before recommending entry."

Mr MacShane has already said he would like to see every British minister becoming minister for Europe. But he is thought to be one of many who believe the government might have to do more to redeem its pro-European credentials in the wake of the decision to back the US in Iraq.

In the June 9 statement Mr Blair kept open the faintest possibility of a euro referendum in this parliament by suggesting that the position would be reviewed ahead of the spring budget.

Some in Downing Street believe the Britain in Europe campaign has suffered due to its close links to the government and think it needs relaunching as a fully independent multi-party campaign.

They say it should now focus on the intergovernmental conference on the future structure of Europe, including the new constitution designed to make Europe more efficient in the wake of enlargement.