The big four supermarkets are expected to be questioned over allegations that they are giving their suppliers an unfair deal, according to newspaper reports.

The Government has expressed concerns about the treatment of farmers and manufacturers by Asda, Tesco, Sainsbury and Safeway/ Morrisons.

Gerry Sutcliffe, competition minister called the supermarket giants to a meeting at which Conservative and Liberal Democrat MPs have also been invited, reflecting cross party concerns.

The Office of Fair Trading ordered the probe into supermarket practices after initial checks indicated that the voluntary code on suppliers was being violated.

The OFT’s concerns include claims the supermarkets are slow to pay suppliers and also that they require suppliers to contribute to marketing costs.