More than 300 former Woolworths stores are still empty a year and a half after the chain collapsed.

The Local Data Company, which provides information on the retail sector, says this represents some 40% of the once-national chain.

The company said some experts believed about 150 stores may never be used as shops again.

The biggest group now using the outlets are discount retailers, including Poundland.

It, along with 99p Stores and B&M Bargains, occupy 25% of former premises.

The next biggest takers of ex-Woolworths stores are supermarkets. New owners include Iceland, which has taken more than 60 premises, and Waitrose.

Less common new uses include a health centre and a library, while a few have reopened stocking a similar range of products under similar sounding names, such as Alworths and Wellworths.

The best take-up of old Woolworths has been in Greater London, where 81% have now been reoccupied, followed by those in Yorkshire and the Humber area at 64%.

Last year the number of empty stores was 60% and one analyst said that despite many stores remaining empty, the latest figures provided some encouraging news of the retail climate.

Andrew Garbutt, retail and leisure director at PricewaterhouseCoopers, said: "The Local Data Company's research shows the UK high street is experiencing a gradual recovery, with vacant ex-Woolworths stores being filled gradually."

Woolworths went into administration in 2008 after facing increased competition from supermarkets and online retailers.