16 May 2016 to shareholders on the register on 8 April 2016. Shareholders may choose to use the Dividend Reinvestment Plan (DRIP) to reinvest the final dividend. The closing date for receipt of new DRIP mandates is 22 April 2016.
Operating cash flow, which is defined as cash generated from operations of £885 million (2014: £765 million) adjusted for capital expenditure (net of proceeds from capital grants) of £411 million (2014: £403 million), and proceeds from the disposal/realisation of fixed assets of £9 million (2014: £19 million), was an inflow of £483 million (2014: £343 million). Included in 2014 operating cash flow is the repayment of principal for a UK Government refundable advance of £38 million. Cash generated from operations includes movements in working capital and provisions totalling a net inflow of £82 million (2014: £33 million outflow). In 2015, the improvement of £115 million was primarily as a result of a substantial one-off customer advance, the VAT on which was repaid in 2016. Capital expenditure (net of proceeds from capital grants) on both tangible and intangible assets totalled £411 million (2014: £403 million). Of this, £330 million (2014: £328 million) was on tangible fixed assets and was 1.5 times (2014: 1.5 times) the depreciation charge. Expenditure on intangible assets, mainly initial non-recurring costs on GKN Aerospace programmes, totalled £81 million (2014: £75 million). The Group invested £157 million in the year (2014: £161 million) on research and development activities not qualifying for capitalisation, net of customer and government funding. Net interest paid totalled £54 million (2014: £83 million, including £16 million of previously accrued interest on a government refundable advance). Tax paid in the year was £111 million (2014: £68 million).
The amount included within trading profit for the year comprises current service costs of £50 million (2014: £49 million), administrative costs of £3 million (2014: £3 million) and a past service credit of £4 million (2014: settlement credit of £9 million). The interest charge on net defined benefit plans, which is excluded from management figures, was £49 million (2014: £50 million). Cash contributions to the various defined benefit pension schemes and retiree medical arrangements totalled £100 million (2014: £108 million).
The accounting deficit for UK schemes decreased to £912 million (2014: £1,005 million), following continued cash contributions from the Group. Both UK pension schemes underwent funding valuations as at 5 April 2013. The agreed deficit recovery plan requires payments of £10 million per year to the pension schemes combined.
Defined contribution pension schemes
In addition to defined benefit pension schemes, the Group also operates a number of defined contribution schemes for which the income statement charge was £42 million (2014: £35 million).
Net assets of £1,886 million were £385 million higher than the December 2014 year end figure of £1,501 million. The increase is driven by management profit after tax of £470 million and a gain on remeasurement of defined benefit plans of £139 million which, in aggregate, more than offsets dividends paid to equity shareholders of £142 million and currency on translation of subsidiaries/equity accounted investments net of tax and the change in value of derivative and other financial instruments of £90 million.
Free cash flow
Free cash flow, which is operating cash flow including equity accounted investment dividends and after interest, tax, amounts paid to non-controlling interests but before dividends paid to GKN shareholders, was an inflow of £370 million (2014: £234 million). The year-on-year change reflects improvements in working capital in addition to the repayment of a government refundable advance in 2014.