Marks & Spencer has increased the time it takes to pay non-food suppliers to reduce costs as it tries to revive its ailing clothing business.Britain's biggest clothing retailer sent letters to its 500 general merchandise suppliers on September 5th outlining the new terms. About 50 are in Britain.Freight-on-board suppliers' payment terms were lengthened to 75 days from 60 days and full-service vendors, which transport, store and deliver the goods, will have their payments times extended to seven weeks from five weeks.The changes will boost M&S's cash-flow but they could prove unpopular. The retailer, led by Chief Executive Marc Bolland, caused uproar two years ago when it asked major suppliers to contribute 1.25% of their annual M&S sales to a store revamp and advertising campaign.M&S's tightening of terms also coincides with political pressure on big companies to pay smaller businesses quicker. Small and medium firms were owed more than £36bn in late payments last year, a parliamentary report said in July.A spokeswoman for M&S said: "Like any company, we are always looking at ways to ensure we are running our business efficiently and that it is well set up for the future. As part of this, we are extending our GM supplier payment terms to bring us in line with industry standards."M&S is trying to revive womenswear sales after two years of falling general merchandise revenues. Some investors have said Bolland's job hangs on turning the clothing business round.