Peter Marks pulls no punches. In March last year he issued a famous rallying cry for the creation of a single co-operative society to replace what had become an "incoherent, fragmented and ill-disciplined organisation with 40 different interpretations of the brand".

It was not empty rhetoric. Last month members of The Co-operative Group and Marks' own United Co-operatives rubberstamped a proposed merger that will unite two of the biggest co-operative groups and give the new group a whopping 80% share of the Co-operative Movement in the UK.

As yet it is not clear whether Marks, who will be running the show as chief executive, will be based at the Co-operative Group's offices in Manchester or United's home turf of Rochdale. What is known is the group will have a turnover of £9.4bn, a total of 87,500 staff and 2,249 food stores, figures that the likes of Asda and Sainsbury's will have taken note of.

Not bad for someone who joined what became Yorkshire Co-operatives in 1967 as a management trainee.

But he does have his work cut out to convince the co-ops that account for the remaining 20% of the sector to merge. One society, East of England Co-op, has already said that it will continue rolling out its own branding.

But he has been here before - having created his own organisation through the merger of the Yorkshire and United Norwest societies - and is already doing a good job of communicating the much bigger rewards likely to be generated by the new merger.

The biggest, of course, is the fact that the Co-operative Movement will finally be able to mount a convincing defence of its territory against the big four. Marks blames them for driving the co-operative societies out of superstores and now trying to do the same with c-stores. His main mission in life, he says, is to stop them.

Following the official merger of the two groups next month, the new super co-op's first priority will be to improve and expand its store portfolio. The current United stores are also set to roll-out 'The Co-operative' fascia, which Marks hopes will be adopted by all societies. In the meantime, the new company is expected to push for further acquisitions.