Former Foreign Office chief Sir Olly Robbins is expected to be grilled by the Foreign Affairs Committee on Tuesday.
The decision to send Peter Mandelson to Washington has become a scandal that just won't go away for Labour.
Last year, the highest proportion of men aged 20-34 were still living at home since at least 2007 as the rising cost of living takes hold.
It comes as a man attempts to ignite a plastic bag containing containing fluid in north-west London.
Nearby Kensington Gardens was closed on Friday and specialist emergency services units were deployed to the site.