Men’s pyjamas, which peaked in popularity in the 1970s when TV comedians Morecambe and Wise wore them in bed, are fashionable again. Sales of full-length night-garments have risen by 30 per cent in the last year, according to market researchers TNS.

Shops say that instead of splashing out money on going out men are lounging around in the evening in pyjamas, while couples spending less in pubs and restaurants are spending more time having sex.

Sales of men’s pyjamas rose from £22m to £33m between 1999 and 2009. TNS’ fashion expert, Elaine Giles, said that pyjamas – derived from the loose-fitting Asian paijama trousers – had become increasingly accepted, particularly among young men.

In 1999, just 4 per cent of male pyjama buyers were under 25; this year the figure was 22 per cent. Over the same period, the proportion of middle-aged and pensioner buyers aged over 55 had dropped from 70 to 40 per cent.

Young men are not the only ones wearing “jim jams” or “PJs”, though; sales of women’s pyjamas trebled in the past decade from £32m to £93m.

However TNS said that the rise in women’s pyjamas was steady, when compared with the surge in men’s pyjamas in the past year.

Debenhams reported a 45 per cent increase in sales of male jim-jams, suggesting that men were changing out of suits and into pyjamas at the end of a hard day.

“Instead of being worn just at night, we have seen a rise in pyjamas as ‘loungewear’. Jersey fabric is now commonly used in pyjamas and is a lot cosier than traditional stiff cotton,” a spokeswoman said.

“Men’s nightwear has shaken off its ‘Wee Willie Winkie’ image and the new designs and fabrics have made them appealing to men and women again.”

At John Lewis, men’s pyjama sales rose 10 per cent on last year, with its own-brand pyjamas doing “extremely well”.

Alongside the demand for pyjamas, shops have noticed a mini-boom in lingerie. John Lewis which reported a 21 per cent spike in contemporary fashion lingerie, said: “Premium-priced pure silk styles have been doing especially well over the last two months showing a 90 per cent increase in sales on last year.

“We have definitely seen a trend for boudoir inspired lingerie as opposed to basic products.”

At Debenhams, sales of basques rose by 45 per cent, suspenders 50 per cent and fishnet stockings 83 per cent. The most popular fabrics were silk, satin, and black lace while animal print was a popular design. The store said: “Many couples in Britain are now spending more time together than ever before and are rediscovering the benefits of nights in.”

At TNS, Elaine Giles said that while, at first hand, increasing sales of hum-drum pyjamas and glamorous lingerie were contradictory, there could be an explanation – while both men and women wanted loose fitting clothing to “slob around in”, women wanted to “make a special effort” to counter that by wearing racy under-garments.