London Stock Exchange Group boss Xavier Rolet has stepped down with immediate effect, blaming "unwelcome publicity" amid a mounting row over succession plans for the top job.

Twenty-one Irish firms have been named among Europe’s top 1,000 high-growth SMEs in a prestigious ranking compiled by the London Stock Exchange.

The London Stock Exchange and German rival Deutsche Borse revealed plans to save more than €448m a year as they agreed a tie-up to create an exchange giant worth more than €26bn.

A rival bidder was today poised to scupper a £4bn (€4.59bn) merger deal between the London Stock Exchange and its Toronto counterpart.

The new head of the London Stock Exchange today said the bourse had cut 133 jobs as rivals eat away at the business.