MILAN: The UK's top share index rose on Wednesday as the pound held its ground after an appeal for party unity from Prime Minister Theresa May over her Brexit plan, while Tesco had its worst trading day in four years after a disappointing update.

The FTSE 100 closed up 0.5 percent to 7,510.28 points, tracking gains across European markets which bounced on easing worries over Italy's budget targets.

May's appeal to her Conservative Party to unite behind her plan for leaving the European Union had little impact on trading, and likewise a survey showing Britain's economy appeared to have kept up most of its steady growth in the July-September period.

Tesco fell 8.6 percent, hitting its lowest since April. Britain's biggest retailer undershot first-half profit forecasts as weak trading in central Europe and Asia took the shine off accelerating sales in its UK business.

"Half year profits missed expectations, but same store sales and margins improved and this, on the whole, can be seen as another positive set of interims from Tesco," said Neil Wilson, analyst at Markets.com.

"This looks rather like expectations had maybe been set a little too high, rather than Tesco underperforming."

Losses in Tesco were more than offset by strength elsewhere, with banks and miners among the biggest gainers.

Aston Martin fell 4.7 percent on its stock market debut after the luxury carmaker priced its shares at 19 pounds each, giving it a valuation of $5.6 billion.

Britain's biggest free-to-air commercial broadcaster ITV  rose 3.7 percent after dismissing reports that it will bid for Endemol Shine.