CARDIFF, WALES - JANUARY 30: Prime Minister Theresa May arrives at Cardiff City Hall for a joint ministerial committee (JMC) which includes the leaders from Westminster, Cardiff, Edinburgh and Belfast on January 30, 2017 in Cardiff, Wales. The Prime Minister's visit to Cardiff today is the first meeting of the joint ministerial committee (JMC) since she announced her priorities for Brexit negotiations. (Photo by Matt Cardy/Getty Images)

CARDIFF, WALES - JANUARY 30:  Prime Minister Theresa May arrives at Cardiff City Hall for a joint ministerial committee (JMC) which includes the leaders from Westminster, Cardiff, Edinburgh and Belfast on January 30, 2017 in Cardiff, Wales. The Prime Minister's visit to Cardiff today is the first meeting of the joint ministerial committee (JMC) since she announced her priorities for Brexit negotiations.  (Photo by Matt Cardy/Getty Images)

CARDIFF, WALES - JANUARY 30: UK Prime Minister Theresa May arrives for a meeting with the joint ministerial committee at City Hall on January 30, 2017 in Cardiff, Wales. The joint ministerial committee (JMC) includes the leaders from Westminster, Cardiff, Edinburgh and Belfast. It is the first time the JMC has been held outside of London. (Photo by Matthew Horwood/Getty Images)

CARDIFF, WALES - JANUARY 30:  UK Prime Minister Theresa May arrives for a meeting with the joint ministerial committee at City Hall on January 30, 2017 in Cardiff, Wales. The joint ministerial committee (JMC) includes the leaders from Westminster, Cardiff, Edinburgh and Belfast. It is the first time the JMC has been held outside of London.  (Photo by Matthew Horwood/Getty Images)

CARDIFF, WALES - JANUARY 30: UK Prime Minister Theresa May arrives for a meeting with the joint ministerial committee at City Hall on January 30, 2017 in Cardiff, Wales. The joint ministerial committee (JMC) includes the leaders from Westminster, Cardiff, Edinburgh and Belfast. It is the first time the JMC has been held outside of London. (Photo by Matthew Horwood/Getty Images)

CARDIFF, WALES - JANUARY 30:  UK Prime Minister Theresa May arrives for a meeting with the joint ministerial committee at City Hall on January 30, 2017 in Cardiff, Wales. The joint ministerial committee (JMC) includes the leaders from Westminster, Cardiff, Edinburgh and Belfast. It is the first time the JMC has been held outside of London.  (Photo by Matthew Horwood/Getty Images)

CARDIFF, WALES - JANUARY 30: UK Prime Minister Theresa May arrives for a meeting with the joint ministerial committee at City Hall on January 30, 2017 in Cardiff, Wales. The joint ministerial committee (JMC) includes the leaders from Westminster, Cardiff, Edinburgh and Belfast. It is the first time the JMC has been held outside of London. (Photo by Matthew Horwood/Getty Images)

CARDIFF, WALES - JANUARY 30:  UK Prime Minister Theresa May arrives for a meeting with the joint ministerial committee at City Hall on January 30, 2017 in Cardiff, Wales. The joint ministerial committee (JMC) includes the leaders from Westminster, Cardiff, Edinburgh and Belfast. It is the first time the JMC has been held outside of London.  (Photo by Matthew Horwood/Getty Images)

CARDIFF, WALES - JANUARY 30: Prime Minister Theresa May leaves Cardiff City Hall following a joint ministerial committee (JMC) which includes the leaders from Westminster, Cardiff, Edinburgh and Belfast on January 30, 2017 in Cardiff, Wales. The Prime Minister visit to Cardiff today is the first meeting of the Joint Ministerial Committee since she announced her intention to negotiate a 'hard' Brexit. (Photo by Matt Cardy/Getty Images)

CARDIFF, WALES - JANUARY 30:  Prime Minister Theresa May leaves Cardiff City Hall following a joint ministerial committee (JMC) which includes the leaders from Westminster, Cardiff, Edinburgh and Belfast on January 30, 2017 in Cardiff, Wales. The Prime Minister visit to Cardiff today is the first meeting of the Joint Ministerial Committee since she announced her intention to negotiate a 'hard' Brexit.  (Photo by Matt Cardy/Getty Images)