sentences:  In 1987–88 Chancellor Nigel Lawson had been following a policy of "shadowing the deutschmark", i.e.cutting interest rates and selling pounds to try to prevent the pound rising above DM 3.00 (as a substitute for joining the European Exchange Rate Mechanism which Thatcher had vetoed in 1985); in an interview for the "Financial Times", in November 1987, Thatcher claimed not to have been told of this and did not approve.By 1989 the economy was suffering from high interest rates (they peaked at 15% in autumn 1989) imposed to temper a potentially unsustainable boom, which she believed had been exacerbated by Lawson's policies.