Exchange rate stability, greater comparability of prices, and larger money and capital markets offer the British economy additional opportunities for growth. It must furthermore be remembered that even if the UK does not join, it will be feeling the impact of EMU. Geographically, the UK may be an island, but it is not economically.
So much is evidenced by the degree to which the British economy is affected by the exchange rate movements of sterling. That influence being as great as it is, then surely it is better to be seated at the table where the policy affecting your economy is determined. That means joining EMU.