LONDON (Reuters) - Former IRA leader Martin McGuinness on Thursday accused Britain of making "very wrong" decisions, saying it was failing to engage with Northern Ireland or take responsibility for the British army's role in a conflict that killed thousands.
Speaking a day after his historic handshake with Queen Elizabeth, McGuinness - now the deputy first minister of Northern Ireland - complained he had met U.S. President Barack Obama more times in his current role than he had met British Prime Minister David Cameron.
"This lack of engagement by David Cameron is a serious mistake," he told an audience at Westminster in London near the Houses of Parliament, which the Irish Republican Army bombed in 1974.
Urging Britain to recognise what he said was its role as a combatant in the Northern Ireland conflict, he accused London of obstructing inquiries into the alleged killings of civilians by the British army and called for greater overall engagement.
"Unfortunately to date the British state has refused to even acknowledge its role as a combatant in the conflict," said McGuinness. "That position is no longer tenable as we move forward. It is insulting to victims."
His meeting with the queen on Wednesday came 14 years after the IRA ended its war against British rule in the province, which is part of the United Kingdom which also includes Britain.
McGuinness said he had met the queen, whose cousin was killed in a 1979 IRA attack, in the spirit of national reconciliation and mutual respect, but that rapprochement was being made more difficult by Britain's "very wrong and unhelpful" decisions.
"We are emerging from a conflict that resulted in lives being lost and families being devastated. I genuinely regret every single life that was lost during that conflict," McGuinness said.
"I am up for the big challenge of redefining that relationship in the wake of this week's historic events. But in the same way as you cannot make peace on your own you cannot build reconciliation without participation," he added.
McGuinness is a hero to Republican hardliners who yearn for a united Ireland, but has long been a hate figure to Unionists who want Northern Ireland to remain part of the United Kingdom, with many of them harbouring deep suspicions about his past.
The IRA ended its 30-year armed campaign against British rule in 1998, but small splinter groups have continued to launch attacks against British targets, though their intensity has fallen sharply in recent years.
McGuinness is a prominent figure in Sinn Fein, Northern Ireland's main pro-Irish nationalist party, which in January proposed a referendum as early as 2016 on whether the province should remain British or join a united Ireland.
McGuinness on Thursday restated his goal of a united Ireland and pushed for "new thinking" in Britain and Ireland, calling the current partition "a relic of the past - a symbol of political failure".
"Is supporting partition really what a modern, forward-looking British government should be doing in the year 2012? I don't think so," he said.
"It is also a challenge for the Irish government. For too long successive Irish governments have paid lip service to Irish unity. They have tolerated the division of our country and people which has resulted in Ireland as a nation not reaching our full potential," he added.
Under a 1998 peace deal, the British government can call a referendum on the future of Northern Ireland if it appears likely that a majority of people in the province want to break with the United Kingdom and form a united Ireland.
However, that seems unlikely in the next few years as Protestants, who overwhelmingly favour remaining in the UK, outnumber Catholics, who usually support the Irish nationalist cause.
Also, not all Catholics want to unite with the Irish Republic, given Dublin's struggles with a deep financial crisis.
McGuinness ended his speech by calling for sensitivity and dialogue ahead of this year's marching season, a time of annual parades by Protestants which usually triggers protests by Catholics that have led to violence in the past.
He also urged those commemorating moments that have defined often troubled Anglo-Irish relations to learn from the past.
"It would be very easy for each of us to select our versions of that history and celebrate and commemorate that with little regard to other events and other versions and indeed the legacy of that entire period," he said.
"We cannot make that mistake. These events will offer a unique opportunity to not just remember but to learn. Not just to commemorate but to understand."
Editing by Andrew Osborn