Wealth inequality in the UK is high and has slightly increased in the past decade due to rising financial asset prices post-financial crisis. Data gaps make it hard to fully understand the distribution and size of household wealth. The main survey captures most wealth distribution, but around £800 billion held by the wealthiest UK households is missing. There is evidence that high-wealth families may undervalue their assets, with the true value of UK household wealth estimated to be 5% higher than reported in surveys.