What do we mean by "levelling up" the UK economy?

This excellent IFS clip looks at the notion of "levelling up" something that Boris Johnson highlighted in his first speech as PM.

It stresses that the UK is one of the most regionally unequal developed countries, and historically the last century has been characterised by persistent regional inequality.

The clip identifies those places in many parts of the UK that are genuinely left behind, the impact of coronavirus and the long-term policies that the government should consider if it is genuinely committed to levelling up. It is mercifully clear and reiterates the need for clear-headed thinking about regional economic policy.