Giving evidence to the Transport Select Committee as it visited Leeds this morning, Ms Brabin said the decision in the Integrated Rail Plan to curtail the Eastern Leg route will have major consequences for the city's economy.
It had been planned that Leeds station would be redeveloped into a T-shaped station designed to deal with HS2 services and local trains.
An initial consultation was first launched on how to accommodate HS2 in Leeds in January 2013 and the option for the T-shaped design was selected in November 2015 - with the hope that it would be the centrepiece of regeneration of the South Bank area and lead to hundreds of millions in private sector investment and more than 10,000 new jobs.
Land around the original station was safeguarded for the planned arrival of HS2 - and despite November's cancellation decision, it remains so. The Government has asked for safeguarding to continue while it carries out a £100m study into how to eventually connect HS2 services to Leeds - including the possibility of reviving the original Eastern Leg plans.
Ms Brabin said: "The safeguarded land is as big as 700 football pitches in the city centre.
"This has been safeguarded for 10 years with the promise of HS2 so it is deeply, deeply disappointing and frustrating."
With the existing Leeds station currently running over-capacity and passengers being subjected to frequent delays as a result, Ms Brabin said the most sensible solution for getting HS2 services into Leeds is to revive the plans to run the route into the city and build the new station.
"The reason that the T-shaped station over many years has become the preferred option is because we need that extra capacity east-west, north-south.
"You can't put a pint in a half-pint pot. We do need that new station."
Ben Still, managing director for the West Yorkshire Combined Authority, said of the land currently set aside for HS2 development: "The city and combined authority will work extremely hard to continue to encourage investment and the successes we have seen in the past, we very much hope to replicate in the future.
"But it is an opportunity that has been foregone in the short-term and we will have to work even harder."
Ms Brabin said earlier in the hearing that she was "perplexed" by the Government's decision not to build HS2 to Leeds and suggested it had been down to financial considerations.
"We're losing those thousands of jobs, those thousands of homes we were planning on. HS2 and Leeds station was going to be part of added value for that area of deprivation and for inward investment.
"The most sub-optimal option was chosen. It can only feel like they have run out of money because the added value is so huge and also chimes so clearly with Government targets on levelling up and the climate emergency. We can only assume it is the cost."
She said it would be "hugely helpful" to have formal Government analysis of how the decision both on HS2 and Northern Powerhouse Rail affects levelling up targets as the technical annexe to the Integrated White Paper revealed that work had not yet been done.
Before the evidence from Ms Brabin and Mr Still, MPs heard from Mark Thurston, chief executive of HS2, who admitted that it is currently unclear what the savings from the downgrade to the HS2 Eastern leg will be.
He said there is "work to do" with the Department for Transport on what the revised route for the Eastern leg will cost.
Instead of reaching Leeds as originally planned, the track from Birmingham will now end at the existing East Midlands Parkway station.
Mr Thurston said that the revised route will run for around 30 miles, whereas the original line was due to be 120 miles long.
He said there would be "physical and technical" challenges to overcome in running HS2 into the existing East Midlands Parkway station.
Labour MP Ben Bradshaw said the committee had spoken to local business leaders in Leeds, who had warned the HS2 curtailment decision would be "catastrophic" for efforts to reach net zero in the region.
Mr Thurston said that while he couldn't comment on the region specifically, more generally high-speed rail was proven to encourage people to use public transport rather than private motor vehicles.
"If you look at where countries around the world have invested in high speed rail they've seen that shift," he said.
"Even in Kent, with High Speed 1 has seen the removal of cars and lorries off the motorways as people are increasingly using the rail network.
"We know that train travel is seven times greener than driving; 17 times greener than flying. So certainly I think once the route from London to Manchester is connected and you can make that journey in an hour and just as we've seen, for example, going from London to Paris that you'd see a shift in time and that in turn has an impact on on the governor's wider commitment for net zero by 2050.
"Our transport system now is the biggest generator of carbon in our economy, bigger than our energy system. And I think train travel has got an important parts of our plans to decarbonising the broader economy."
Huw Merriman, chair of the Transport Select Committee, asked Mr Thurston whether he agreed the decision to scrap HS2 represented a "massive missed opportunity".
He said: "If you look at the community here, the Eastern leg would have improved connectivity for 13 million people - 20 per cent of the population. Currently, 72 per cent of all journeys are undertaken by car in this area.
"This just feels like a massive missed opportunity.
"Does it sadden you that the great project that you thought would be the Y-connection all the way up to the two big cities in the North, Manchester and Leeds, is now not going to occur?"
Mr Thurston replied: "The Government made a difficult decision around the IRP.
"The work we need to do around Manchester means the journey time between Manchester and Leeds will significantly reduce in the fullness of time.
"Clearly the journey time between the West Midlands and Leeds will be significantly reduced when we have built the Eastern Leg. We'll need to work out how we flight trains to Leeds.
"The Government has made the decision. Our focus now is how do we organise ourselves and resource ourselves to support the department for delivering the Eastern Leg?"
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