3. Investments

Sundry investments
At 1 January 2013400.00.6400.6
At 31 December 2013400.00.6400.6
Provision for impairment
At 1 January 20137.47.4
At 31 December 20137.47.4
Net book value
At 31 December 2013392.60.6393.2
At 31 December 2012392.60.6393.2

The sundry investments relate to the Bodycote Investment Incentive Plan, as explained in the Board Report on Remuneration.

Details of principal subsidiary undertakings of the Company are shown in Principal subsidiary undertakings.