Trade and other liabilities

12 Months Ended

Dec. 31, 2017

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Trade and other liabilities

24. Trade and other liabilities

All figures in £ millions	2017		2016
Trade payables		265		333
Social security and other taxes		21		25
Accruals		447		507
Deferred income		322		883
Interest payable		45		31
Liability to purchase own shares		151		—
Other liabilities		224		272
		1,475		2,051
Less: non-current portion
Accruals		26		17
Deferred income		35		319
Other liabilities		72		86
		133		422
Current portion		1,342		1,629

The carrying value of the Group’s trade and other liabilities approximates its fair value.

The deferred income balance comprises advance payments in assessment, testing and training businesses; subscription income in school and college businesses; and obligations to deliver digital content in future periods.

The liability to purchase own shares relates to a liability arising under a buyback agreement for the purchase of the company’s own shares (see note 27).