Alistair Asher, the general counsel of the Co-operative Group, was on a higher basic salary than the average FTSE 30 legal chief even before news of the group's above inflation pay review emerged at the weekend.

Leaked details of the Co-op's executive remuneration review – first disclosed by The Observer at the weekend and since seen by Legal Week – show Asher's current basic salary of £475,000 is at the top end for UK listed companies.

The review proposes Asher's total target remuneration should increase to £1.2m for 2014. The sum would be made up of a £550,000 base salary, a £550,000 bonus and other fixed allowances.

The leak of the pay review details has caused a major headache for the struggling mutual, and was a catalyst for the resignation earlier this week of chief executive Euan Sutherland (pictured), who called the organisation "ungovernable".

Critics have suggested the pay proposals for management jarred with the principles of the Manchester-headquartered consumer cooperative.

Co-op chair Ursula Lidbetter said the increases reflected "the greater commercial, management and turnaround experience of the team".

According to market data obtained by the Co-op, the base salary for executive committee roles in the FTSE 100 ranges between £360,000 and £400,000, rising to between £425,000 and £475,000 for FTSE 30 companies.

Although the market data research does not give the top end of the scale for legal heads, the recommendations state the "base salaries for [chief executive of retail] Steve Murrells, [executive director] Nick Folland and Alistair Asher are already above upper quartile".

Average profits per equity partner at Asher's previous firm, Allen & Overy, stood at £1.1m in 2012-13, although he is likely to have earned substantially more as the firm's global financial institutions head .

The Co-op justified the increase for its executive committee because of the difficulties facing the group, and because it wants to retain the executives throughout a three to four-year transformation period.

"The executive agenda is possibly the most complex one facing a large business in the country today," the document states.

Challenges facing the executives include "fixing a business on the verge of financial collapse, turning around the food business after years of neglect, reforming a membership system that is faltering from a fundamental disconnect [and] effecting a major governance change".

Asher was parachuted into the Group general counsel role last July, following the identification of a £1.5bn capital shortfall in the Co-op Bank.

Since stepping into the role, Asher – a banking lawyer – has lost ultimate oversight of the Co-op Bank's legal function, after the Group ceded majority control of the lender in a deal with bondholders last year.

Under the previous arrangement the bank's legal services were provided by the Group. Asher now works closely with bank GC Brona McKeown, who was installed in November and reports to the bank's chief executive Niall Booker.