Tesco is likely to post its poorest sales performance for 20 years, with the supermarket operator expected to show its first drop in like-for-like sales in its domestic market since the 1990s.

Although the company will not officially release its results until Wednesday, Tesco’s like-for-like sales for the six months to August are expected to feature a fall of 1 per cent, according to financial analysts.

With UK shoppers increasingly focused on making savings, even on food spending, the rate of sales decline for the summer months could be even worse, said The Guardian, with decreases of up to 2 per cent likely.

The expected fall in sales coincides with the launch of Tesco’s Big Price Drop promotional campaign, under which the prices of over 3,000 items - including fruits and vegetables - will be cut by as much as 30 per cent.

However, Dave McCarthy, an analyst from Evolutions Securities, told the Press Association that the initiative was indicative of the “serious issues” the retailer faced.

For the UK’s third-largest grocery retailer, Sainsbury’s, the picture is expected to be little better. The company, which also releases its results on Wednesday, is likely to report that underlying sales in the 16 weeks to 1 October rose by only 0.7 per cent.