Tory welfare chiefs have been slammed after admitting a vast review of disability benefits has repaid just a few thousand people   Ministers originally said up to 220,000 people would get higher Personal Independence Payment (PIP) following a High Court victory  That would have helped around 14% of the 1.6million people on PIP.   But a year since a review of all cases began, just 3,500 of the first 440,000 people – 0 8% – have received extra benefits.  That is despite more than 250 extra staff being hired to work on the review, which is not expected to finish until next year  Charities and MPs demanded an investigation into why the number of repayments was so much lower than expected  Ayaz Manji of mental health charity Mind said he was “incredibly alarmed”, adding: “If this is due to an error in the way these numbers were estimated, this is an error of monumental proportions    “There will be thousands of people with mental health problems who will rightly be worried that the Government have not upheld their commitment to review their claims fully and fairly  “We need to see an independent investigation to understand what has gone wrong here and what action the Department for Work and Pensions needs to take to fix it ”  Marsha de Cordova, Labour’s Shadow Minister for Disabled People, added: “These figures are truly shocking  “We were told 14% of people on PIP whose cases are being reviewed would get more cash Instead just 0.8% of them have got that support, which they desperately need.  “Without PIP, many sick and disabled people will be left destitute  “The DWP must urgently answer why there is such a significant disparity between the department’s estimate and the results    “Many disabled people will understandably fear that this is yet another error by a shambolic Tory-run DWP ”  PIP is worth up to £148.85 a week to fund costs of being disabled, and the average back payment has been £4,500 per person  The review is thanks to a 2016 tribunal, which ruled people who suffer “overwhelming psychological distress” travelling alone should qualify more easily   At first ministers rewrote the law to avoid paying higher PIP. But they U-turned after the High Court  ruled the government’s behaviour was “blatantly discriminatory”  Ministers began reviewing cases in June 2018 and promised to fund back payments dating to November 2016  In 2017 officials claimed the U-turn would cost £3.7bn in five years.  And speaking in January 2018, then-welfare chief Esther McVey said “it could affect up to 220,000 people ”  But today the Department for Work and Pensions (DWP) said it had “always been clear this was an estimate”  DWP officials said their original estimates were produced before final guidance for implementing the judgement was drawn up  They insisted that guidance had been drawn up with key organisations including Mind  A DWP spokeswoman said: “We are committed to ensuring that disabled people and those with health conditions get the support they are entitled to, and the proportion of people with mental health conditions who get the higher rate of PIP is five times higher than under DLA  “We have always been clear that this was an estimate which was produced before we knew the full detail of who would be eligible  “We have assurance processes in place so that this is done in full and fairly and we are on track to complete the exercise by 2020 ”