* FTSE 100 up 0.5%, FTSE 250 adds 0.9%

July 21 (Reuters) - UK shares jumped on Tuesday, tracking gains in Europe after EU leaders reached a "historic" stimulus deal to shore up economies battered by the pandemic, while Ted Baker surged on saying its performance was ahead of a base case scenario.

Shares of Ted Baker soared 10.8% and were on course for their best day in more than a month as the struggling fashion retailer also said its online sales jumped 35% for the period ended July 18.

The blue-chip FTSE 100 gained 0.5% and the mid-cap FTSE 250 rose 0.9%, led by autos, banks and real estate stocks.

Stock markets in Europe surged to their highest in more than four months following the massive stimulus plan that paves the way for the European Commission, the EU's executive arm, to raise billions of euros on capital markets on behalf of all 27 states.

However, Ladbrokes owner GVC Plc slumped 7.9% after saying British tax authorities had expanded an investigation into the gambling company's former online business in Turkey to include unidentified entities within the group. (Reporting by Sagarika Jaisinghani in Bengaluru, Editing by Sherry Jacob-Phillips)