The Mayor of London announced the plans on December 6, bringing step free access to 30 tube stations to make it the biggest boost in the network's 153 year history.
Part of the draft Business Plan, Transport for London (TfL) has committed to making selected stations step-free by 2022, including Harrow On The Hill.
Long standing campaigners in the area joined Assembly Member Navin Shah to celebrate the success after fighting for disability access for nearly 15 years.
"The previous Mayor, Boris Johnson , withdrew funding and halted works to make this station accessible and failed to respond to growing concerns about poor accessibility for disable, elderly people and parents with buggies at this station."
Mr Shah also thanked the Mayor and Deputy Mayor for Transport Val Shawcross' "proactive nature" towards the cause and described the new administration at City Hall "refreshing".
The long campaign for step free access at Harrow on the Hill
With Harrow being identified as an "opportunity area", campaigners argued the station was not fit for purpose for many years.
But the team were dealt a severe blow in 2014 when the then Mayor Boris Johnson pulled promised funding of £25 million , which the Harrow Association of Disabled People described as "horribly disappointing".
Mr Shah, who spearheaded the campaign, said the public transport hub has to also meet the borough's future expansion plans, with regeneration happening fast in the town centre.
After Sadiq Khan hinted at step free access for the station during the People's Question Time , hopeful stakeholders who had invested into rallying locals for the cause waited with baited breath for an announcement.
Groups including Harrow Association of Disabled People (HAD), Harrow Mencap and the Harrow branch of Age UK were delighted with the news.
Ann Groves who had fought for access had told getwestlondon : "I would very much welcome on behalf of everyone at HAD any effort to bring step-free access to stations in Harrow.
"You do not have to be disabled to be inconvenienced by the lack of step-free access.
"You only have to have a minor problem, or a suitcase of a baby in a buggy and it is not even going up the stairs that is the only problem – you have also got to go back down on to the platform."
Watch the struggle disabled passengers face getting around London
Bond Street, Tottenham Court Road and Victoria are also on the way to becoming step-free in 2017, making it easier for elderly, infirmed and children with buggies.
The Mayor of London, Sadiq Khan, said: "As part of making London’s transport system one of the very best in the world we must ensure it is accessible for all Londoners.
"It’s simply not right that for people with disabilities, parents with young children and many older people, many of our stations are still very difficult to use.
"I promised in my manifesto that we needed to be more ambitious with our approach to step-free access, and I’m confirming that £200m will be invested on the Underground over the next five years."
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