Tony Blair will be allowed to lobby the Government on behalf of the bank that has appointed him as an adviser.

Mr Blair confirmed yesterday that he had taken a job with JP Morgan Chase, the financial services and investment banking group. The bank said that he would provide political and strategic advice. He is expected to earn more than £500,000.

Mr Blair, who, as Prime Minister, left most issues about international finance and the economy to Gordon Brown, said that he had taken the role because he was interested in the impact of globalisation on commerce. Mr Blair is on course to become the richest former premier in recent history.

The Advisory Committee on Business Interests, which vets the jobs of former ministers to ensure that there is no conflict of interest, advised Mr Blair that he could take up the job immediately “but for one year after leaving office he should not be personally involved in lobbying government ministers or officials on behalf of his new employer or its clients”.

The watchdog has no power to prevent Mr Blair from lobbying if he chooses, beyond naming and shaming him on its website. It gave the green light to Mr Blair’s speaking engagements, but warned him not to “draw on privileged information that was available to him as Prime Minister”.

Jamie Dimon, JP Morgan’s chief executive, said that he had telephoned Mr Blair. “I went to visit him and we hit it off.”

To deflect criticism, Mr Blair, who is in Jerusalem, pledged to spend at least ten days a month on his role as peace envoy in the Middle East. An ally said that he “feels he owes it to the Middle East, after Iraq, to stay with the region and do what he can to address the central question of Palestine”.

He is seeking “a small handful” of similar appointments in different sectors. This may be supplemented by a role on climate change. He is believed to have turned down approaches from HSBC and Citigroup. The job was brokered by Robert Barnett, the Washing-on lawyer who negotiated the reported £5 million advance for his memoirs.

Mr Blair has mortgages of £4 million on various properties. He is making between £500,000 and £1 million a month from speaking engagements, matching the earning power of Bill Clinton.

On Sunday he will address up to 5,000 people in Universal City, near Los Angeles, for the American Jewish University. The most expensive ticket, at £1,200 includes a reception, dinner and photograph with Mr Blair. Last night there were tickets available for $42.50 (£21.50), discounted from $85.

On January 17 Blair will address 2,000 people at the Westin Harbour Castle in Toronto. The event is sponsored by TD Bank Financial Group.

Des Turner, the Brighton Kemptown Labour MP, said: “He’s cashing in big time. It’s one law for some and another for the rest.”

Gerald Howarth, the Conservative defence spokesman, said: “I think it will be viewed with some contempt by the Armed Forces that he picks up this large cheque when he was happy to send British troops into battle ill-equipped and in insufficient numbers.”

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