The pound's value measured against a basket of other currencies, including the dollar and the euro, has reached its highest level for more than 4 years.
The trade-weighted index stands at 85.0. It was last at that level on 5th August 2009, during a rally as the financial crisis and recession began to take hold.
The pound has been surging ahead amid growing hopes about the scale of the economic recovery.
The called the trade-weighted index, called the effective exchange rate by the Bank of England, shows the pound's value in comparison to the currencies of our main trading partners.
The index was based at 100 in January, 2005. It fell to 74 in late 2008.