England will allow fully vaccinated visitors from the European Union and United States to arrive without quarantining from next week, the transport minister said, in a long-awaited boost for airlines and travel companies.
The domestically focused mid-cap index ended 0.6% higher at 23006.45, but had hit record highs earlier in the day, with travel related stocks Wizz Air, SSP Group and Easyjet among the biggest gainers.
"It is another hurdle knocked over in the attempt to offer the industry some semblance of a summer season ... but questions remain about just how many tourists will come flocking, given that travel to the UK still isn't advised for U.S. tourists," said Susannah Streeter, senior analyst at Hargreaves Lansdown.
The blue-chip FTSE 100 index rose 0.3% led by gains in precious and base metal miners.
Also supporting the blue-chip index was British lender Barclays, which ended 2.0% higher after its first-half profit nearly quadrupled and said it would pay out more than a billion dollars in dividends and buybacks.
St James Place and Fresnillo were the top two gainers on the FTSE 100 on positive earnings updates.
Wednesday's gains bring the FTSE 100's rise so far this year to 8.3%, underperforming the 12.3% climb in mid-cap stocks in the same period as inflation concerns and a surge in local COVID-19 infections drag on investor sentiment.
Among stocks, Wizz Air jumped 4% to be the top mid-cap gainer after it said it expected to ramp up capacity to between 90% and 100% of pre-pandemic levels this month and next, as summer demand for European travel grows.
Aston Martin added 2.4% after it reported a 224% increase in sales to its dealers, boosted by its first sport utility vehicle.
Travel stocks boost UK midcaps 
(Reporting by Shashank Nayar in Bengaluru; Editing by Subhranshu Sahu, Uttaresh.V and Alison Williams)
By Shashank Nayar
