A ‘£40,000-a-year’ senior council executive was paid more than £500,000 for just under two years work, an official report has revealed.

David McElhinney, the former boss of Lancashire County Council’s One Connect partnership with telecoms giant BT, received two lump sums of £231,709 and £275,888 in June and July this year without the knowledge of county treasurer Gill Kilkpatrick, the council document said.

He officially worked just two and half days a week for Lancashire and was also receiving an unknown amount from a similar partnership between BT and Liverpool City Council, called Liverpool Direct Ltd, for the other half of the working week.

The council said it was now investigating how the two lump-sum payments from its bank account were authorised.

The report said his salary as a Lancashire County Council employee was ‘£40,000 a year’ plus bonuses under the original agreement in 2011.

In January, 2013, his status was upgraded from director to executive director but Ms Kilpatrick was not aware of any increase in remuneration.

Details of the payments are revealed in a ‘bombshell’ report to the council’s Audit and Governance Committee, which meets on Monday.

Blackburn MP Jack Straw said: “These are quite extraordinary revelations.

“This is twice what the Prime Minister gets for working seven days a week.”

Pendle Liberal Democrat peer Lord Greaves said: “How did this happen? This level of pay is quite extraordinary.”

Mr McElhinney, who last month quit his job as chief executive of One Connect and LCC executive director transformation, said: “I worked for BT 5 days a week as CEO of both LDL and OCL. I was appointed to both posts by BT.”

One Connect was established in May 2011 to save the council £400million over 10 years.

Around 800 county council and BT employees were seconded to staff it.

The report to the audit committee on the council’s accounts is required by law and includes a special section on the payments.

It comes on top of the suspension earlier in August of county chief executive Phil Halsall after it was alleged that favouritism was shown towards BT in the bidding process for the council’s £5million fleet maintenance service contract.

The report said that in May 2011 then county Tory leader Geoff Driver agreed a report from Mr Halsall outlining the One Connect deal and the appointment of Mr McElhinney as ‘an employee of Lancashire County Council’.

It tells councillors for 2.5 days a week working for Lancashire ‘the salary for this role was £40,000 a year, which recognised that Mr McElhinney would continue to receive a salary from Liverpool City Council’.

The report said that he ‘was entitled to significant bonus arrangements, access to lease car and access to private medical insurance’.

It reveals that in June 2013 he was paid a lump sum of £231,709 for the period May 16, 2011 to March 31, 2012, made up £135,338 salary, and bonus payments of £189,229.

In July 2013 Mr McElhinney was paid a second lump sum of £275,888 for April 1 2012 to March 31 2013 made up of £159,675 salary, £116,213 bonus payments and lease car payments worth £10,643.

The payments were made out of a Lancashire County Council bank account on behalf of One Connect. The authority paid another £69,700 for his National Insurance Contributions to the taxman for the two years.

The report said Ms Kilpatrick only became aware of the payments last month when preparing the accounts because no normal monthly salary payments had been made to Mr McElhinney over the two years.

It said: “The county council’s authorisation for these payments is currently under review.”

County deputy leader David Borrow, said: “Details of these payments have only come to light in recent weeks and we are publishing them now as part of the routine process of setting out the council's annual accounts.

“Leader Jennifer Mein has directed that arrangements are made for the whole matter to be investigated and reviewed independently, including the scale of the sums involved and the process by which the payments were made. Payments of this size for 2.5 days a week, twice the salary of the chief executive, are outrageous."

Former Lancashire County Council Tory leader Geoff Driver said: “I am seriously concerned about the way this matter has been expressed.

“As for the amount of information that has been included in the report, it goes way, way beyond what is required to comply with the requirements of the legislation.

“The entire sum was reimbursed by One Connect and guaranteed by BT. It comes from the initial £3million per annum guaranteed by BT to cover the senior management costs of One Connect.”