RETAILER WH Smith has upgraded its full year profit forecast after hailing another strong performance at its travel arm over the festive period.

The firm said like-for-like sales at its travel arm, which includes stores at airports and railway stations, rose five per cent in the 21 weeks to January 21.

This offset a three per cent fall in comparable sales across high street stores and left overall group sales up two per cent and one per cent on a like-for-like basis.

Chief executive Stephen Clarke said: "In travel, we have delivered good sales growth across all our key channels in the period.

"This was driven by ongoing investment in the business and continued growth in passenger numbers - particularly in our airport stores over the Christmas holiday period.

"As a result of the performance in travel we expect group profit growth for the year to be slightly ahead of plan."

The company has been boosted by surging demand for food on the go across its stores based in airports and railway stations.

The dip in high street sales was explained by strong promotional activity and tough comparatives from last year when it saw strong sales of "colour therapy" titles.

Nevertheless, Mr Clarke described high street figures as a "good performance" and in line with expectations, pointing to strong sales of spoof humour books.

He added: "While there is some uncertainty in the broader economic environment, we remain confident that the Group is well positioned for the year ahead as we continue to focus on profitable growth, cash generation and investing in new opportunities."

Total travel sales rose 10 per cent while high street sales dipped four per cent over the period.