Speaking to BBC Radio 4’s Today Programme Gisela Stuart said looking at the figures, a Labour government was unlikely.
Quizzed on whether she wanted Mrs May or Mr Corbyn in charge of Brexit-Britain, she said: “It is unlikely, if I look at the figures, that we will have a Labour government.
“So what I want is actually a strong representation of the Labour Party in the House of Commons.”
Appearing stunned, the BBC host pushed: “You’re saying it’s unlikely Labour will be elected?”
Gisela Stuart said it was 'unlikely' that Jeremy Corbyn would be any challenge to the Tories
To which Ms Stuart said: “If I look at the figures it is unlikely that Labour will have a majority to form a government on its own.
“I think it will be safest when you have got all the voices represented, therefore I want a solid number of Labour members of Parliament.”
The admission came after the shadow chancellor was hammered on the programme for dodging questions about Labour’s Brexit stance.
Challenged on whether Labour wanted the UK to stay inside the single market, he said: “Access to the single market. We’ll want to negotiate tariff-free access to the single market, that’s been one of our priorities, to protect jobs and the economy overall.
“We believe we can negotiate with our European partners a managed and fair immigration system from the EU which takes into account the needs of our economy.
It is unlikely, if I look at the figures, that we will have a Labour government
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“And all the discussions we’ve had with our socialist and democratic party colleagues across Europe have given us an indication that they’re looking for a constructive relationship based upon mutual interests.”
Quizzed on the customs union and if Britain would seek to do its own trade deals under Jeremy Corbyn’s leadership, Mr McDonnell said: “What we would seek to do is maximise the opportunities that we now get from the customs union and again that will be a part of negotiations.”
However, as Mr McDonnell launched a tirade against Mrs May for calling a general election instead of following the path she had been expected to follow, the BBC host reeled him in and insisted the electorate wanted to know Labour’s stance.
Mr McDonnell was asked: “Would you like Britain to be doing its own trade deals around the world or would you like us to stay in the customs union?”
Live from 10 Downing Street: Theresa May calls snap general election Tue, April 18, 2017
Theresa May has made the announcement to call for an early general election to be held on June 8 2017
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Britain's Prime Minister Theresa May speaks to the media outside 10 Downing Street, in central London
To which the politician responded: “We want to ensure we maximise the benefit that we currently have with regards to our relationship via the customs union.”
Having none of the evasiveness, the host snapped: “That is not a clear answer for the electorate!”
Theresa May stunned her political opponents on Wednesday as she called for a general election to be held on June 8.
In her speech announcing the snap election, the PM took a swipe at bitter Remainers trying to scupper the UK’s departure from the European Union.
She said: "I have just chaired a meeting of the Cabinet, where we agreed that the Government should call a general election, to be held on June 8.
"At this moment of enormous national significance there should be unity here in Westminster, but instead there is division. The country is coming together, but Westminster is not.
"In recent weeks Labour has threatened to vote against the deal we reach with the European Union. The Liberal Democrats have said they want to grind the business of government to a standsill.
"The Scottish National Party say they will vote against the legislation that formally repeals Britain's membership of the European Union. And unelected members of the House of Lords have vowed to fight us every step of the way.”