In initial deals, London's benchmark FTSE 100 index rose 0.2 percent to 7,302.28 points, compared with Wednesday's closing level.

In the eurozone, Frankfurt's DAX 30 index fell 0.3 percent to 11,566.87 points and the Paris CAC 40 retreated 0.1 percent to 5,378.41.

British Prime Minister Theresa May heads back to Brussels on Thursday on a last-gasp mission to beg EU leaders for more time to deliver a Brexit deal twice rejected by her own parliament.

May declared late Wednesday that she is "determined" to deliver Brexit, after formally requesting a three-month delay to Britain's departure from the bloc.

With just eight days until the country's four-decade-old European Union membership comes to an abrupt end, the 27 other EU leaders are losing faith in May's ability to ratify an orderly withdrawal.