Double buggy in London?

[WeAllLikeVindaloo]

Im running the London marathon this year.

I have a 2 & 3 year old.

3 year old mostly walks fine. 2 year old obviously gets tired quickly so we use a pram. I have an out n about double nipper too.
Will it be doable to use the double for travelling around London on the underground? I know it’s going to be super busy that weekend so I would like to keep the 3 year old contained in busy areas.
or would it be easier using two single strollers?