The decision by retailer Marks & Spencer to slash its returns policy from 90 days to just 35 days has led to some shoppers threatening to boycott the chain.

The store made the changes to its three-month "no quibbles" refund policy back in April, but consumer groups and the media have only now latched on to switch.

Even though the new terms are detailed on receipts, along with the last date on which a purchase can be returned, the move has angered thousands of customers who say they will now be stuck with unwanted items.

Consumer watchdog Which? says the "drastic" change should have been made clearer to M&S customers, particularly when the generous returns policy was a stand-out feature of the shopping experience at the high street chain.

And it warns the retailer could lose business as a result.

"Marks and Spencer seem more concerned with comparing themselves to other high street brands instead of standing out to its loyal customers - and not publicising such a drastic change is slack," said Which? shopping researcher Sarah Dennis.

"Any high street shop that is aiming to bring its policies in line with its competitors rather than going the extra mile for its shoppers may see a shift in shoppers' loyalty.'

A spokesman for Marks & Spencer defended the change however, telling just-style that it reviewed its returns policy "in line with the market and it still remains one of the best on the high street."

"We offer our customers a full refund or exchange on goods returned within 35 days, which compares favourably to our competitors, many of which offer just 28 days.

"The last date for return is clearly printed on the till receipt and the overwhelming majority of our customers return unwanted items well within this period."

Although he wouldn't say whether the retailer would revert back to the 90-day policy following the negative publicity, it has however extended its Christmas returns policy.

Any gifts purchased between 1 October and 11 December can now be taken back to its stores until 16 January.

This latest set-back for M&S comes three months after it was forced to drop a GBP2 surcharge on larger-sized bras after internet protests pointed out other high-street lingerie retailers were offering one price across all sizes.

The retailer, which is due to release a second-quarter trading update on Wednesday (30 September) has also been hit hard by the economic downturn as shoppers shunned its stores for cheaper rivals.