Away from the NE, there looks to be a cracking week in prospect. Never as warm in the West, but there should be sunshine on offer at times. The Midlands and especially the SE should have some wonderful spring weather to start April. A UK max of 21C Wed and Thurs, somewhere in, or within striking distance of London? Quite possible. 25C? Maybe. A date record on Wed (presently) 23.9C, 75F in Leeming (N Yorks) in 1946)? Not impossible, IMO; it is going to be very warm, for some.
http://www.torro.org.uk/site/hightempsyear.php