The pound reached a seven-year high against the euro after the European Central Bank launched a programme to buy government bonds.
Sterling reached €1.40 for the first time since December 2007 on Tuesday, an increase of 0.45% in one day.
The currency movement followed a tense meeting between eurozone finance ministers on Monday that ended with the Eurogroup chief Jeroen Dijsselbloem telling Greece to "stop wasting time".
Greece's creditors are eager to see a detailed list of economic reforms before they release further financial aid to Athens.
The Greek government agreed to extend its economic bailout by four months in February, although it has yet to flesh out its austerity measures.
The leftist-dominated government won national elections in January after it campaigned hard on an anti-austerity ticket.
However, the uncertainty over Greece's future in the bloc and the slow pace of economic recovery have weighed on the euro.
Announcing the details of the quantitative easing programme last week, ECB president Mario Draghi said he expected economic growth within the euro area to reach 1.5% this year, up from a previous forecast of 1%.
Inflation would climb to 1.8% in two years, he said, but would fall to 0.0% for 2015. The ECB is supposed to keep inflation at 2%, or just below that level.
Lower oil prices would provide another boost to the eurozone economy, he said.