Analysts have warned the London Stock Exchange it should not assume its Italian banking owners will be long-term shareholders, after one unexpectedly sold off its stake at a discount last night, causing heavy losses to the LSE share price this morning.

Shares in Europe's largest equity market traded down 6.2% this morning to £17.70 a share at 12:00 GMT, having opened today at £18.86 a share. Last night Banca Monte dei Paschi di Siena, the world's oldest bank, put up for sale 2.9% of LSE stock at £17.70 a share.