The FTSE 100 was up 0.5% and the FTSE 250 was up 0.6% by 0725 GMT, ahead of GDP data.

China on Thursday appealed to Washington to meet it halfway to salvage a deal that could end their trade war, with talks between Chinese Vice Premier Liu He and U.S. representatives set to resume on Friday.

Asia-exposed financial heavyweights HSBC and Prudential rose as a result, while hopes of easing tensions also helped copper prices and guided miners higher.

The higher U.S. tariff "marks a sharp escalation in the trade spat, but it's not gone nuclear yet," Markets.com analyst Neil Wilson said.

In corporate news, British Airways owner IAG advanced 4.6% after it posted quarterly results in line with expectations.

But AstraZeneca slipped 1.3 percent after an anemia treatment developed by the company and its partners did not show a meaningful difference in risk of major adverse cardiac events against Pfizer's approved drug.

Among small stocks, London-listed shares of platinum miner Lonmin tumbled 6.1% after it said annual sales would be at the lower end of its target range, partly due to delays in a takeover by Sibanye-Stillwater.

Thomas Cook gained 5.5% after a Sky News report on Thursday that Virgin Atlantic had tabled an offer for the tour operator's long-haul unit.