The increase in deaths has been coming down pretty solidly for the last couple of days, so we could be past the peak now if we're lucky. I think time will tell whether that ends up being the case. Lockdown is next due to be reviewed on 13th April, but I don't personally see it ending that early unless the government either massively changes its strategy or there's a stark decrease in cases & deaths. Presuming they add another 3 weeks onto the timeline (when lockdown was originally announced, they said it would be reviewed every 3 weeks), the earliest I can see the measures being lifted is 4th May.
I could actually see them being lifted on this date, because the government is said to be getting fed up of the economic impact, and some people advising the government have even suggested that we revert back to our former herd immunity strategy. Boris Johnson is reported to be wanting to get us out of lockdown "as soon as possible" and was quite hesitant to introduce it, so I think that as soon as there's evidence of substantially reducing case numbers, we'll be out and about again.