| £ Millions | Development costs | Brand | Trademarks | Technology | Customer
relationships | Customer contracts | Intangible software | Intangible software
under development | Total |
| Cost | | | | | | | | | |
| At 1 January 2017 | 25.0 | – | 1.0 | 0.7 | 0.7 | 0.1 | – | – | 27.5 |
| Additions | 5.2 | 0.1 | – | 1.6 | – | – | – | – | 6.9 |
| Acquisition of business | – | – | – | – | 4.9 | 0.3 | – | – | 5.2 |
| Foreign currency translation | (1.2) | – | – | – | (0.1) | – | – | – | (1.3) |
| At 31 December 2017 | 29.0 | 0.1 | 1.0 | 2.3 | 5.5 | 0.4 | – | – | 38.3 |
| Additions | 6.2 | – | – | – | – | – | 0.2 | 1.1 | 7.5 |
| Reclassification from property, plant and equipment | – | – | – | – | – | – | – | 0.5 | 0.5 |
| Acquisition of business | – | 0.8 | – | 2.6 | 12.1 | 0.2 | – | – | 15.7 |
| Foreign currency translation | 1.2 | 0.1 | – | 0.3 | 1.0 | – | – | 0.1 | 2.7 |
| At 31 December 2018 | 36.4 | 1.0 | 1.0 | 5.2 | 18.6 | 0.6 | 0.2 | 1.7 | 64.7 |
| Amortisation | | | | | | | | | |
| At 1 January 2017 | 10.8 | – | 1.0 | 0.1 | 0.2 | 0.1 | – | – | 12.2 |
| Charge for the year | 2.5 | – | – | 0.1 | 0.4 | 0.1 | – | – | 3.1 |
| Foreign currency translation | (0.3) | – | (0.1) | – | (0.1) | – | – | – | (0.5) |
| At 31 December 2017 | 13.0 | – | 0.9 | 0.2 | 0.5 | 0.2 | – | – | 14.8 |
| Charge for the year | 2.9 | 0.1 | – | 0.5 | 1.8 | 0.4 | * | – | 5.7 |
| Foreign currency translation | 0.4 | – | – | 0.1 | 0.1 | – | – | – | 0.6 |
| At 31 December 2018 | 16.3 | 0.1 | 0.9 | 0.8 | 2.4 | 0.6 | * | – | 21.1 |
| Carrying amount | | | | | | | | | |
| At 31 December 2018 | 20.1 | 0.9 | 0.1 | 4.4 | 16.2 | – | 0.2 | 1.7 | 43.6 |
| At 31 December 2017 | 16.0 | 0.1 | 0.1 | 2.1 | 5.0 | 0.2 | – | – | 23.5 |
*Balances are less than £100,000.
The amortisation period for development costs incurred on the Group's products varies between three and seven years according to the expected useful life of the products being developed.
Amortisation commences when the product is ready and available for use.
The remaining amortisation period for customer relationships ranges from three to nine years.