LONDON (AFX) - Britain faces slow economic decline if it does not join the euro soon, a group of top business leaders warned in a letter to The Times newspaper. The seven businessmen called for early euro entry, which they said would save British companies 4.5 bln stg and enable them to compete more effectively in international markets. Signatories include Andreas Kark, managing director of DaimlerChrysler UK Holdings; Danny Bernstein, managing director of Monarch Airlines; and Massimo Carello, executive chairman of Diners Club UK. They wrote: "We cannot fully benefit from the euro as long as we remain outside. By joining, we would no longer waste 4.5 bln on administration costs when converting from one currency to another. "Much more importantly, the pound's instability outside our largest export market is undermining our ability to compete effectively. "The arrival of euro notes and coins is a tangible reminder that the status quo is no longer an option. "Britain must choose between increasing prosperity by joining a successful eurozone or risk facing slow economic decline caused by turning our backs on Europe. "As individuals from a variety of industry sectors and company sizes, we believe it is important to end the uncertainty and make that choice soon." Also signing the letter were Nicholas Brookes, chief executive of Spirent; Dinesh Dhamija, chief executive officer of ebookers; George Kessler, managing director of Kesslers International; and Lynn Wood, managing director of Adastra Software.