The London Stock Exchange Group is to provide real-time market data to Google, bolstering the search-engine's Google Finance offering with free access to London prices previously only available with a delay.

The move, aimed at retail investors, demonstrates the growing power of the internet to deliver data available to subscribers of specialist services such as those provided by Thomson Reuters and Bloomberg LP.

The deal only covers the last price traded. LSE will not provide data such as bid-offer spreads on which professional traders depend.

Google already provides real-time share data from the New York Stock Exchange, the Nasdaq, and exchanges in China and India. Google Finance, which competes with a similar offering from smaller rival Yahoo, is funded by advertising.

Other share prices are provided with a 15 minute delay.

"The addition of real-time quotes from the London Stock Exchange and Borsa Italiana will enable our users to better monitor market changes, manage their portfolios and track economic and financial developments in Europe," Maxim Edelman of Google Strategic Partnerships said in a statement on Tuesday.

Edelman had already announced the new real-time quote services from the London Stock Exchange, Germany's Deutsche Boerse and Italy's Borsa Italiana on the Google Finance blog (http://googlefinanceblog.blogspot.com).

The LSE's data business is its fastest-growing unit. Its revenues rose 24 percent to 52.8 million pounds ($83.8 million) last quarter, accounting for 27 percent of group revenue. ($1 = 0.6301 British pounds)