Outsourcing firm Capita was the leading gainer, up by 4% after a reassuring trading statement.
The company, which in February warned of lower margins, said it was on track to meet expectations for 2016 revenue growth. The statement was described as "unusually numbers light" by one broker.
The FTSE 100 was up 38.92 points at 6,153.73.
Shares in Easyjet, which reported a loss - largely thanks to adverse currency movements - fell 0.4% after its gain of 3.8% on Monday.
There was the usual volatility in mining stocks. On Monday the index was dragged down by these with Anglo American losing 13.8%. Morning Tuesday trade sees them recover 3.4%.
On the currency markets, the pound rose 0.21% against the dollar to $1.4438 but was flat against the euro to â‚¬1.2669.
(Open): London's FTSE 100 started higher on Tuesday.