| 16 | Trade and other receivables |
| 2017 | 2016 | 2015 | ||||||||||
| £’000 | £’000 | £'000 | ||||||||||
| Trade receivables | 2,232 | 1,428 | 985 | |||||||||
| Prepayments | 627 | 586 | 685 | |||||||||
| Other receivables | 848 | 873 | 1,213 | |||||||||
| Total trade and other receivables | 3,707 | 2,887 | 2,883 | |||||||||
| Less: non-current portion (rental deposit and on bond) | (465 | ) | (448 | ) | (387 | ) | ||||||
| Current portion | 3,242 | 2,439 | 2,496 | |||||||||
Trade and other receivables do not contain any impaired assets. The Group does not hold any collateral as security and the maximum exposure to credit risk at the Consolidated Statement of Financial Position date is the fair value of each class of receivable.
Book values approximate to fair value at 31 December 2017, 2016 and 2015.