LONDON, March 15 — Strength in oil majors coupled with optimism that a Brexit delay would help avert a disruptive no-deal departure helped Britain’s main bourse rise for a fifth straight day, while Frankie & Benny’s owner Restaurant Group jumped on strong earnings.

The FTSE 100 advanced 0.5 per cent and the FTSE 250 outperformed with a 0.8 per cent gain by 1007 GMT. Ireland’s main index, often considered a gauge of Brexit mood, added 0.6 per cent.

All three indexes outshone their European peers.

Britain’s parliament approved asking the European Union for a short delay if lawmakers can agree on a Brexit deal by March 20, or a longer delay if nothing can be agreed in time.

"This means that for now the prime minister has managed to retain control of the Brexit process and can resurrect her rather battered withdrawal agreement for another vote,” CMC Markets analyst Michael Hewson said.

The main index found its biggest support in heavyweights Shell and BP that added 1 percent each as US crude prices hit their highest this year on OPEC-led production cuts and US sanctions against Venezuela and Iran.

Stocks deemed to be less risky at times of economic uncertainty also contributed to gains with consumer giant Unilever, tobacco firm British American Tobacco and pharmaceutical company GlaxoSmithKline rising.

Spreadex analyst Connor Campbell said the need for the EU to unanimously approve any delay meant some uncertainty remained, thus drawing investors to defensive stocks.

Housebuilders, considered to be among most vulnerable to economic hits stemming from Brexit, rose on the back of yesterday’s vote and after Berkeley’s trading update.

Berkeley added 2 per cent after it stuck to its profit target despite softness in Britain’s housing market caused by Brexit uncertainties.

Meanwhile, Asia-exposed stocks such as HSBC, StanChart and Burberry were lifted after a media report that Chinese Vice Premier Liu He spoke with US representatives and that further progress had been made on trade talks.

A stand-out winner on the midcap index was Restaurant Group, which surged 10.2 per cent — its biggest rise in two years — as like-for-like sales rose 2.8 per cent in the 10 weeks to March 10 and 2018 profit exceeded its forecast.

But Bakkavor slipped 5 per cent as Berenberg cut its rating and said it believes UK food manufacturers are "not as tasty as they look” with shoppers spending more cautiously.

Troubled outsourcer Interserve shot up by 14 per cent after slumping as much as 8 per cent, ahead of a shareholder meeting on whether to accept a rescue deal or let the small-cap company fall into administration. — Reuters