LONDON, Dec 19: The ‘debacle’ of Iraq and Tony Blair's failure to influence US policy will overshadow his time as prime minister, said a paper published by a leading UK think-tank, Chatham House, on Tuesday.

Quoting the paper, “Blair’s foreign policy and its successor (s)”, a press release of Chatham House said: “It’s ‘unforgivable’ that Tony Blair saw too late the consequences of Taliban resurgence in Afghanistan.”

The paper observed that Tony Blair had failed to influence the US policy despite the sacrifice -- military, political and financial -- that the UK has made.

Responding to the paper, which assesses British foreign policy since 1997, Foreign Secretary Margaret Beckett said: "This paper is threadbare, insubstantial and just plain wrong. Chatham House has established a great reputation over the years, but this paper will do nothing to enhance it."

In the assessment of the paper Mr Blair learned the hard way that loyalty in international politics counts for nothing and his successor will not make the same mistake of offering unconditional support for US initiatives in foreign policy at the expense of a more positive relationship with Europe.

The paper predicts that the two main candidates to be prime minister in the next five years will have to rethink Britain’s role within the European Union. This is likely to be uncomfortable for both Gordon Brown, with his strong Atlanticist leanings and his strident criticism of lagging Eurozone performance, and David Cameron, who has already indicated his preference to align with eurosceptic European parties. But, the report argues, closer links with Europe will be a requirement in the coming years despite, at present, British influence being strictly limited and the British public still uncomfortable in its European skin.

According to the paper, the invasion of Iraq was a ‘terrible mistake’ and the absence of a UN Security Council resolution authorising the use of force drove a ‘horse and cart’ through Mr Blair’s self-proclaimed doctrine of international community. The post-invasion ‘debacle’ has undermined British influence internationally and over crucial issues, including a two-state solution in the Middle East. A distancing of the UK from the US and a closer relationship with Europe has been advised as requirements of post-Blair foreign policy. However, the UK will have to work, the paper said, to be taken more seriously by its European partners. This will require the UK to rethink its opposition to joining both the Schengen agreement and the Eurozone.