In a revealing interview with the Sunday Times Magazine, the PM described Britain as going through a “moment of change” that is “highly challenging”.
May said the country “had to get on” with a Brexit deal and revealed her faith helps her decide what is right and wrong when it comes to making the big decisions.
She said: “I suppose there is something in terms of faith, I am a practising member of the Church of England and so forth, that lies behind what I do. It’s not like I’ve decided to do what I’m going to do and I’m stubborn.
“I’ll think it through, have a gut instinct, look at the evidence, work through the arguments, because you have to think through the unintended consequences. But ultimately, if you’ve done all that and you believe it’s the right thing to do , then you should go and do it — but sometimes it is difficult.”
May will today host a summit meeting with Polish counterpart Beata Szydlo as she attempts to build alliances ahead of the Brexit negotiations.
Szydlo said she would be a constructive partner in the negotiations but warned there would need to be compromises in the talks between the UK and European Union.
Senior ministers from both countries will take part in discussions on security co-operation and strengthening business and cultural links between the UK and Poland.
Further details of a planned deployment of 150 British troops to Poland will also be revealed as part of the measures being taken by Nato to provide support for the country amid concerns about Russian military activities.
During the visit May and Szydlo will discuss Brexit and defence co-operation over a working lunch while senior ministers - including Foreign Secretary Boris Johnson and Chancellor Philip Hammond - will meet at Lancaster House.
The leaders and ministers will then come together for formal talks in the Cabinet room at Number 10 to discuss issues ranging from trade and scientific co-operation to Moscow’s actions in Ukraine and Syria.
As part of the visit, more details will be set out about the deployment in April next year of around 150 troops from the Light Dragoons regiment in Catterick, along with a number of armoured vehicles, to Orzysz in north-east Poland, close to the border with the Russian enclave Kaliningrad.
May said: “Our ties with Poland are rooted deeply in our shared history. We will never forget the Polish pilots who braved the skies alongside us during World War Two, standing up for freedom and democracy in Europe, nor the valuable contribution made by so many Poles in our country today.
“I am determined that Brexit will not weaken our relationship with Poland, rather it will serve as a catalyst to strengthen it. That’s why I am hosting the first ever summit of this kind between our countries today.
“It marks the start of a new chapter in our relations and we will work even more closely together to ensure the security and prosperity of our nations in the years ahead.
“Today’s meeting puts beyond doubt the common ground we share, the importance we attach to our bilateral relationship and the benefits it brings. We share a clear commitment to take our co-operation to the next level and to firmly establish the UK and Poland as resolute and strategic allies in Europe.”
May has vowed to trigger Article 50, the legal process for Brexit, by the end of March and while formal negotiations on the UK’s divorce settlement with Brussels cannot begin until that time, the Prime Minister is keen to hold informal talks with European leaders to gauge their views.
Writing in the Daily Telegraph, the Polish prime minister said: “Warsaw will certainly be one of the capitals which will participate in Brexit negotiations in a constructive and down-to-earth manner.”
She added: “We hope, as I believe the rest of the EU hopes, that Britain’s new relationship with the EU will be as close as possible, and based on the principles of proportionality and balance of rights and obligations.
“Whether we manage to complete this arduous task of bringing negotiations to a satisfying result will depend solely on our imagination and leadership. We need a good compromise which gives both our countries the best possible options for economic and security co-operation.
“Poland will be a constructive partner in this process, as we have been in the past – but the initiative for determining British ambitions and expectations as to the future level of co-operation with the EU has to come from London.”
May has said she wants to guarantee the rights of EU citizens in the UK but will not do so unless she receives reciprocal assurances from her counterparts on the continent and Szydlo called for agreement from the bloc.
“One thing is certain: millions of UK citizens living across the EU and millions of EU-27 citizens living in the UK should not be made to feel like hostages,” she said.
“Our common duty should be to ensure their maximum security and prosperity, wherever they have chosen to live. That means we have to guarantee not only their right of residence but also the proper coordination of social security systems on both sides of the English Channel.”
Warsaw has raised concerns about the abuse of Poles in the UK following the European Union referendum, with a rise in incidents of alleged hate crimes including the killing of Arkadiusz Jozwik in Harlow, Essex.
The two prime ministers will jointly host a reception in Downing Street to pay tribute to the contribution made by Poles in the UK as part of an effort to strengthen ties.
Addressing around 50 members of the Polish community, May is expected to praise the role they play in sectors such as business, medicine, academia and the arts and reiterate her strong condemnation of the attacks against Poles in the wake of the referendum result, underlining that hate crime of any kind has absolutely no place in British society.
May will also launch a British-Polish Civil Society Forum, which will meet for the first time in Warsaw next year. This annual event will bring together business leaders, communities, academics and journalists.