15 Available-for-sale investments

2010
£m 		2009
£m
1 January 83 106
Differences on exchange (1) (2)
Additions and advances 1 251
Revaluations 4 3
Disposals and repayments (275)
31 December 87 83
 
Current 58 57
Non-current 29 26
87 83

The classification of these investments under the IFRS 7 fair value hierarchy is given in note 24.

Investments have the following maturities:

As per balance sheet
2010
£m 		2009
£m
Equity investments 30 28
Non-equity investments
– within one year 44 44
– beyond one year and within two years 11 6
– beyond two years and within three years 1 5
– beyond five years 1
87 83

There is no material difference between the maturity profile of investments in the table above and the maturity profile on a contractual gross basis where the values in each year include the investments maturing in that year together with forecast interest receipts on all investments which are due for all or part of that year.

Investments are denominated in the functional currency of the subsidiary undertaking or other currencies as shown below:

2010
£m 		2009
£m
Functional currencies 83 79
US dollar 2 2
Other currencies 2 2
87 83

Non-equity investments of £57 million (2009: £55 million) are principally denominated in UK sterling and have an effective interest rate of 1.4 per cent (2009: 4 per cent).