ONS data shows average life satisfaction, purpose and happiness ratings have all increased among Britons in the 12 months leading up to July 2017.
The figures are based on a nationwide survey in which the ONS asked respondents to rate how they felt about their lives.
Between June 2016 (when the UK voted to leave the European Union) and July 2017, Britons scored an average of 7.7 out of 10 for life satisfaction, 7.9 for feeling what they do in life is worthwhile and 7.5 for happiness.
This is up from 7.6, 7.8 and 7.4 out of 10 respectively between June 2015 and July 2016 and the highest level since the ONS began recording life satisfaction in 2011.
The data also shows anxiety has not increased over the past year, with the average Briton ranking their feelings of anxiety as 2.9 out of 10 for the past two years in a row.
Reasons given for the spike include a fall in unemployment – with the UK now boasting the highest number of people in work since 1975 – and an increase in average wealth and national disposable income per head.
In addition, the ONS said there was evidence Britons are less worried about the implications of Brexit than they were previously.
Pointing to recent research by IPSOS Mori, the ONS observed that the number of people who believe the UK’s exit from the EU will “have no effect” on their lives has risen from 24 per cent in October 2016 to 40 per cent in March 2017.
The report concludes: “This possibly implies that as time goes on people are becoming more relaxed about the implications of Brexit.”
Figures showed regional disparity, however, with England driving almost all of the gains. No changes in reported personal well-being were found in Scotland, Wales or Northern Ireland.
The ONS warned the tide may also be turning.
Despite improvements in employment, GDP per capita and national disposable income, the body reported that real household disposable income per head has fallen for the fourth quarter in a row.
The report said: “For the first time in two years, UK consumers reported a worsening perception of their own financial situation in April to June 2017.”
In addition, the ONS observed that the effects of Brexit are still unknown and largely unfelt by the general public:
It found: “Another thing to note is that although Article 50 has been triggered, we have not yet left the EU and hence the implications on the daily lives of people in the UK remain to be seen.”