Shares in Domino’s Pizza fell nearly 7% after it delivered disappointing news on its sales growth.
In the six months to 25 June, UK like-for-like sales growth at the FTSE 250 firm slowed to 2.4% from 13% last year.
The news overshadowed a 9% increase in profits for the half year to £44.6m,
Virgin Money was another FTSE 250 member having a bad day. Its shares fell 5.5% after the bank warned there could be some “areas of weakness” in the UK housing market.
However, Virgin said the housing market should remain “resilient”, and it reported a 26% rise in half-year underlying profits to £128.6m.
London’s benchmark FTSE 100 share index was up 63.72 points, or 0.9%, at 7,441.45 shortly after midday.
Top riser was media group Informa, which rose 6.8% after it reported a 40% rise in half-year revenues thanks to strong trading at its global exhibitions business.
Back in the FTSE 250, Acacia Mining shares were down a further 12% as investors reacted to news that the company had been handed a $190bn bill for unpaid taxes and penalties from Tanzania.
The company has been accused of under-reporting export revenues, which Acacia denies.
On the currency markets, the pound edged up 0.05% against the dollar to $1.3034, and was down 0.1% against the euro at 1.1182 euros.