Teresa May didn’t introduce austerity. Cameron and Osborne did.
Not forgetting the EU's role of course;
"On 5 December 2017, the Council closed the excessive deficit procedure for the United Kingdom, confirming that its government deficit has dropped below the EU’s 3% of GDP reference value."
"It abrogated its 2008 decision on the existence of an excessive deficit in the UK."
"As a result, only two of the EU's 28 member states remain subject to excessive deficit procedures.This continues an improvement observed since 2010-11 when, during a 12-month period, procedures were open for 24 member states."
"The UK has been subject to an excessive deficit procedure since July 2008, when the Council called for its deficit to be corrected by the 2009-10 financial year."
"However the 2008 economic downturn, as well as stimulus measures adopted in response to the downturn, led to a substantial deterioration in the UK's budgetary position."
"In April 2009, the Council extended the deadline for correcting the deficit by four years, to the 2013‑14 financial year. In December 2009 it extended it by an additional year, to 2014‑15, in the light of unexpected adverse events.The contraction in economic activity in the UK had worsened to 3.3% of GDP, and the projected government deficit for 2009‑10 had been revised upwards to 13% of GDP."
"In June 2015, the Council granted the UK a further two years to correct its deficit. It recommended headline deficit targets of 4.1% of GDP in 2015-16 and 2.7% of GDP in 2016-17, consistent with improvements in the structural balance of 0.5% and 1.1% of GDP respectively."
"Over the period, the Council found twice, in April 2009 and June 2015, that the UK had not taken effective action in response to its recommendations. But as the UK is not in the eurozone, fines could not be imposed."
www.consilium.europa.eu/en/press/press-releases/2017/12/05/uk-s-deficit-back-below-3percent-of-gdp-council-closes-procedure/