By lunchtime the FTSE 100 was up 0.4% to 7,537.07 as oil majors BP and Royal Dutch Shell reacted to rising energy prices on turmoil in the Middle East.
The pound fell amid ongoing political ructions in the UK with Boris Johnson widely expected to prevail in the Conservative Party leadership contest tomorrow.
Fashion brand Ted Baker was up 14% on weekend press reports that founder and major shareholder Ray Kelvin is open to the idea of buy-out of the business. Kelvin departed amid allegations of misconduct earlier this year.
LARGE AND MID CAP RISERS AND FALLERS
Business-focused media company Ascential rose 3% on announcing that it had agreed to acquire an initial 35% interest in cybersecurity provider Avast's marketing analysis unit Jumpshot for $60.8m alongside a solid set of first half results.
Ascential also assumed an option to take a controlling stake in Jumpshot. Avast shares rose 0.8%.
Challenger bank Metro Bank advanced 5.6% after it confirmed media speculation that it was in talks to sell a loan portfolio.
Premier Inn hotel chain owner Whitbread reversed 3.8% on announcing that it had completed a £2.5bn capital return funded by the sale of its Costa coffee business.
SMALL CAP RISERS AND FALLERS
Recruitment company SThree gained 2.6% after it reported a 28% rise in first-half profit, as growth in its overseas businesses more than offset weakness in the UK.
Petra Diamonds fell 5.6% on the back of 6% slide in annual revenue hurt by lower gem prices. The company also forecast lower production volumes in the current financial year.
Workplace digital learning company Learning Technologies jumped 19% after it guided for full-year earnings 'materially ahead' of market expectations.
Bioplastics and radio frequency technology business Biome Technologies sank 12% on warning that it expected to post a 'modest' first-half loss, as sales fell and it invested in more staff.
Tiziana Life Sciences was flat after earlier enjoying double-digit gains as it reported positive results from a clincial trail assessing the safety of a treatment for hepatocellular carcinoma, the most common form of liver cancer.
Scientific instrument group Judges Scientific fell 0.3% amid a small contraction in its second-quarter orders.