Core borrowings which exclude PFI/PPP non-recourse borrowings, are all long term. During the year, we issued a 3.65% €100m Green retail bond in the Belgian market, our third bond issue in Belgium, but our first Green bond. A bond can only be classified as Green if the funds raised will be used for sustainable purposes, which is the case for almost all of the investments made by Shanks. In October 2015 we redeemed our first Belgian retail bond. We also redeemed in June 2015 our PRICOA senior notes of €40m which were at a fixed interest rate of 5.025%.
At 31 March 2016, the Group’s bank financing comprised a €180m multicurrency revolving credit facility with seven major banks entered into on 31 January 2014 and expiring in January 2019. At 31 March 2016, €77m equivalent of the facility was drawn. The margin varies on a ratchet fixed by the Net Debt:EBITDA ratio. As announced on 5 April 2016, the financial covenants of this facility were amended to extend leverage and reduce the total net worth requirement. These amendments provide further flexibility while we complete the build phases on our Derby and Surrey PPP contracts and will give further protection against currency fluctuation as the EU referendum approaches. The principal covenants are the ratio of Net Debt:EBITDA of less than 3.5:1, interest cover of not less than 3.0:1 and a minimum net worth of £175m. The six year retail bonds of €100m, issued in July 2013 to investors in Belgium and Luxembourg have an annual coupon of 4.23%, are quoted on the London Stock Exchange.
The Group also has access to £25.1m of undrawn uncommitted working capital facilities with various banks. Cash flows are pooled at a country level and each operation is tasked with operating within the limits of the locally available working capital facilities.
Debt borrowed in the special purpose vehicles (SPVs) for the financing of UK PFI/PPP programmes is separate from the Group’s core debt and is secured over the assets and future cash flows of the SPVs with no recourse to the Group as a whole. Interest rates are fixed by means of interest rate swaps at the time of contract inception. At 31 March 2016 the UK PFI/PPP borrowings were £91.1m (2015: £222.6m). The significant decrease in the year arose following the disposal of 49.99% of the equity in the Wakefield contract on 30 March and the consequent equity accounting for our remaining interest as a joint venture.