(ii) Deferred tax
The Group makes provision for deferred tax on temporary differences where tax recognition occurs at a different time from accounting recognition. Deferred tax assets of £1,079 million were recognised as at 31 December 2017 (2016 - £1,391 million).
The Group has recognised deferred tax assets in respect of losses, principally in the UK, and temporary differences. Deferred tax assets are recognised in respect of unused tax losses and other temporary differences to the extent that it is probable that there will be future UK taxable profits against which the losses and other temporary differences can be utilised.
The Group has considered the carrying value of the deferred tax asset as at 31 December 2017 that, based on management’s estimates, sufficient taxable profits will be generated in future years to recover recognised deferred tax assets. These estimates are based on forecast performance and take into account Brexit, the Group’s plans to implement the UK ring-fencing regime and the resultant transfers between members of the Group.
Deferred tax assets of £1,886 million (2016 - £2,665 million) have not been recognised in respect of tax losses and other temporary differences where the availability of future taxable profits is uncertain. Further details about the Group’s deferred tax assets are given in Note 23 on the accounts.