'As a share of GDP' - are the critical words!
The actual National Debt will continue to increase every year - and is expected to exceed £2T by 2020.
OBR, ONS, the Tories etc. - all agree on this; but the GDP percentage reduction is welcome. However, as yet, it is just a projection.
It's nearly 50 years since the Tories achieved an actual National Debt reduction - a point which will be emphasised in the financial media tomorrow.
Hammond has been impressive and honest about the unsafe level of Debt - and the admission that it has doubled since his party returned to government in 2010.