By Iona Bain

Retail giant Tesco has risen from the ashes after its shock profits warning last Thursday, becoming the most bought share of the past week.

The supermarket giant topped the table of customers' buys at TD Direct Investing and accounted for half of the top ten buys for the execution-only stockbroker in the past seven days.

Stuart Welch at TD Direct Investing said customers "were looking for a bargain" after Tesco announced that like-for-like sales had fallen 2.3% and profits could be in freefall, prompting its share price to collapse by 20%.

Sainsbury's also saw its share price fall by 9% on the back of Tesco's announcements, as retail analysts surmised that tough times lay ahead for the supermarket sector as a whole. But it has made a strong comeback, making no.6 in the list of most bought shares this week.

Tesco and Sainsbury's could be classed as cyclical stocks that are more vulnerable to economic turmoil, but other popular shares this week were noticeably defensive, such as the oil and gas explorers Red Emperor Resources and Range Resources, both of which confirmed last week that they would begin drilling an exploration well at a key site in Somalia.

But frantic trading of bank shares continues - Royal Bank of Scotland was the most sold share of the past week, followed by Lloyds Banking Group and Barclays. However, RBS - which is part-owned by the taxpayer - was also the fifth most popular buy among investors.

Investors with strong stomachs can buy shares on an individual basis but they must be confident, disciplined and prepared to do their research. If you're uncertain about where to start, you can consult a financial advisor here.