Old support marks resistance in the quid's recovery
After bottoming out at 1.2444 we've seen a recovery up to 1.2490. The 1.2480/90 level was support through yesterday and thus we're finding it as resistance on the way back up.

GBPUSD 15 m chart
EURGBP is in a similar position, albeit in reverse. Later yesterday 0.8500 was resistance and it's not support.
There's been some support also from a bounce in yen crosses which weakened generally during the morning. Both GBP and EUR vs JPY have crept back up adding support to the majors.
We'll see how US traders set their stalls out as they arrive on the scene shortly, and all eyes will be on Yellen later today.