Heading into the last hour of trading UK shares have once more given up earlier gains.

In a near-mirror image of Monday's trading, shares in London have lost ground in the afternoon after a promising - albeit modest - start. It is the mining sector that has proved to be the overall winner today, lifted early on by news from BHP Billiton - the company announced that it had come to an agreement with some of its Asian steel mill clients to sell iron at a price based on short-term contracts. This looks to be a significant change from the previous way of doing things (based on annual contracts) and in theory it should provide a greater degree of transparency to the business on both sides. The short-term benefit is that the miners will receive more for selling their iron ore. Unsurprisingly, this information was well-received by investors.

The revision to UK fourth quarter GDP data was the main economic event of the day, with this getting pushed out to 0.4% growth, which was slightly better than expected.  Market reaction was negligible at best though - the data is probably more useful as a political football at this point - with the market more concerned about whether the current quarter's data is going to show that the recovery is being sustained.