Yes - as noted earlier, that's one of the reasons China can't currently be considered as a realistic contender for a reserve currency, let alone a viable replacement for the USD.
It was Major, not Thatcher, and it wasn't pride but their ERM obligations to other EU countries which required them to prop up the currency value - but yes, it was disastrously stupid to make the attempt (they managed to burn £3.3 billion before figuring that out!) - though in the long term, that damage 20 years ago is probably a fraction of the damage we'd have suffered if the crisis had hit later on when it was harder to escape, as Greece and Ireland have found.Too much pride in the value of your currency goes before a fall, as the Thatcher government discovered when they nearly bankrupted the Treasury trying to support the GBP above the market's valuation.