High street giant John Lewis bucked the trend yesterday revealing sales up by nearly one-third last week - but bosses warned that the year ahead would still be tough.

High street giant John Lewis bucked the trend yesterday revealing sales up by nearly one-third last week - but bosses warned that the year ahead would still be tough.

The department store said that its sales increased by 27.4% compared to the same period the previous year. Trading was particularly strong on the Monday and Tuesday after Christmas and the Friday after New Year.

Management hailed the results as "truly inspirational" but stressed that the economic downturn still signalled difficult times ahead.

Glasgow performed the best of the chain's three Scottish branches, with sales up 20% on last year, followed by Aberdeen, which was up 19.3% and Edinburgh, up 10.2%.

Best-sellers north of the border ranged from TVs and digital cameras to designer handbags and swimsuits.

John Lewis head of selling development Barry Matheson said that a number of factors may have worked in the chain's favour during the week.

He said: "Was it the fall of the calendar? Was it the weather? Was it driven by constant media reports of the bargains to be had? It is difficult to tell, but what we know for sure is that we delivered a truly inspirational result last week with sales 27% ahead of last year."

A spokeswoman stressed that the rise was partly because of the way the dates fell, with week 23 starting just one day after its sales, which always begin on December 27, compared to last year when week 23 did not start until December 30.

In Glasgow, store managing director Lesley Ballantyne said: "Our sales were very good but obviously it is going to be an incredibly difficult year in retail. We are not expecting phenomenal growth as a result of last week."

Meanwhile Waitrose, the upmarket John Lewis supermarket chain, revealed that it had identified a site for its first store in Glasgow.

A spokesman said it hoped to open in the city "as soon as possible".

Waitrose opened its first Scottish branches in Edinburgh in 2006 in Comely Bank and Morningside. Six months later managing director Steve Epsom indicated that the company was looking for further new sites north of the border, but so far it has yet to open any more branches in Scotland.