His polling and market research company, CTF Partners, billed more than £2.4 million ($4.93 million) to the Conservatives in the year leading up to the vote, according to figures released today by Britain's Electoral Commission.

The biggest bill was £390,200 ($801,561), for "tracking polls, focus groups and ad hoc polls", billed in late February as the election campaign heated up.

But it was not the only bill that month – the company also charged a £63,600 ($130,649) "consultancy fee".

The next month saw another bill for £245,200 ($503,697) come through, plus the regular consultancy fee.

Political blogger Guido Fawkes calculated that CTF's bill made up 15 per cent of the Conservative Party's total £15.5 million ($31.84 million) election budget.

"Given the against-the-odds result, that surely represents great value for money," Fawkes wrote.

The party also spent £369,000 ($758,011) on the services of former Obama campaign guru Jim Messina, and £1.2 million  ($2.47 million) on Facebook advertising.

The BBC calculated that the Conservatives spent £1.38 ($2.83) per vote, compared with £1.29 ($2.65) for Labour, £1.46 ($3) for the decimated Liberal Democrats, and just 73p ($1.50) for UKIP.

Sir Lynton was knighted in the New Year honours, in a list that was widely criticised for rewarding undeserving political donors and supporters – of all parties.

Fairfax contacted Sir Lynton for comment, and in reply CTF sent a prepared statement.

A spokesman for CTF Partners said in the statement the company deployed a team of "up to 10" working full-time on the election campaign, which was represented by the consultancy figures released on Wednesday.

"We are proud of the roles they played in the victory," the spokesman said.

"We are also proud of our extensive research work – represented by the research figures - and how this highly targeted strategy ultimately proved successful in delivering a Conservative government.

"Any claim that these figures represent Lynton Crosby's salary is wrong and deliberately misleading."