Government advisers have warned ministers that a tighter lockdown will lead to a second outbreak of coronavirus later this year.

Putting in place "very stringent" measures of the sort seen in Hong Kong and China could just delay the peak until after the restrictions were lifted, potentially into the autumn, official modelling found.

It comes amid repeated warnings from ministers that the Government will tighten social distancing measures, including a ban on exercising outdoors, if it is shown that people are not complying with the rules.

Senior police officers have warned that any further restrictions would be difficult to enforce.

The Scientific Advisory Group for Emergencies (Sage) report on the "potential impact of behavioural and social intervention" casts doubt on whether a tighter lockdown would be effective. It shows that the largest number of deaths would occur if there was no intervention, which in the UK was estimated at around 500,000.

If some measures were implemented to "moderately reduce transmission", which could include people changing their behaviour without intervention, then the deaths would have reduced slightly and the peak delayed, the summary, presented to the Government last month, concluded.