MPs are demanding the City watchdog probes suspicious market movements around the release of official government statistics.
Reports this week have highlighted unusual fluctuations in both foreign exchange and bond markets around the release of economic data, such as that relating to retail sales.
One analysis found eight occasions over the last year in which the pound moved before the publication of numbers from the Office for National Statistics (ONS), correctly anticipating the directionthe currency would move after the official release.
Earlier this week Reuters reported an incident from February in which sterling fell by around 20 ticks to $1.244 in 15 seconds, three minutes before retail figures were published.
And now a powerful committee of MPs is calling for an investigation.
In a letter to the City regulator, Treasury committee chair Andrew Tyrie, said: "The Financial Conduct Authority will want to consider this matter, if it is not already doing so, given one of its objectives is to protect and enhance the integrity of the UK financial system."
The Financial Conduct Authority declined to comment.