The main stock market index swung between gains and losses in early deals, and was roughly flat by 0710 GMT, while the mid-cap FTSE 250 outperformed with a 0.5% rise.

AstraZeneca added 4% to top the blue-chip index after it raised its annual product sales forecast, but the gains were offset by steep, post-earnings losses in spirits company Diageo, analytics provider Relx and software provider Sage Group.

Cobham soared more than 34% to 165 pence, matching the 165 pence per share offer price from U.S. private equity group Advent International.