The FTSE 100 gained 0.4pc and the FTSE 250 rose 0.2pc by 0706 GMT, tracking gains in Asian stock markets as investors cheered the agreement between the United States and its southern neighbour .

Gains were spread largely across the board in London, with heavyweight financial stocks, miners and oil shares all boosting the FTSE 100.

Plumbing products distributor Ferguson's shares lost 4.1pc after the company's third-quarter revenue missed analysts' expectations.

Woodford Patient Capital Trust, a FTSE 250-listed fund run by money manger Neil Woodford, tumbled another 5pc, despite reassuring investors that the suspension of a flagship equity fund had not affected its "operational performance".

Thomas Cook, which has put its tour operating business up for sale in the aftermath of three profit warnings in the past year, surged 11.8pc after it said it was in talks with Fosun, already the company's largest shareholder.