The UK Government's facing scrutiny by the Welsh Affairs Select Committee.
They'll be demanding to know why the previous Prime Minister agreed the case for rail electrification to Swansea, but now following the Brexit vote, the Government has done a U-turn.
The committee will also demand to know why ministers are dragging their feet over making a decision on the tidal programme - when it's had clean bill of health from an independent enquiry.
Geraint Davies Labour MP for Swansea West has secured Parliamentary enquiries into both projects.
He told us: "The Welsh Affairs Select Committee has the exceptional powers to summon Ministers and other witnesses to give evidence. We'll be demanding to know why the previous Conservative Prime Minister agreed the case for rail electrification to Swansea but now, following the Brexit vote, the Government plans to break that promise.
"David Cameron as Prime Minister said that rail electrification to Swansea would have a 'huge impact' on spreading jobs in an area that had been neglected of infrastructure investment. This was following a delegation I lead of four councils, two universities, industry, MPs and AMs to make the case for Swansea being part of the Europe-wide electric rail network in order to encourage inward investment. That case is now stronger than ever.
"Thanks to my proposal, Ministers will be in the hot seat to answer how they justify cutting Swansea rail investment to pay towards the cost of paying towards UK debts for leaving the EU.
"In addition, I've secured an enquiry into the Swansea Bay Tidal Lagoon to put pressure on the Government to get it built without further delay.
"We've had enough Conservative foot-dragging already. George Osborne praised our Lagoon in the 2014 as did David Cameron so now that we've had a clean bill of health from an independent enquiry, the Hendry Report, there's no excuse for delay.
"Ministers will be made to sweat as they try to explain why, at a time that eighty per cent of fossil fuels can't be used if we are to avoid irreversible climate change, they are subsidising fracking instead of supporting green energy. We want a Lagoon in the Bay not fracking in the Gower.
"Thirdly we are doing a report on the impact of Brexit on Wales and this will again be uncomfortable for Ministers as they try to explain why every family in Wales will now pay thousands towards our EU debt costs on leaving the EU after being promised more NHS cash. Also 25,000 Swansea Bay jobs would be put at risk if the Government walk away from the European Single Market so Ministers need to face up to their responsibility to give the people the final say on the Exit Deal if it doesn't match what was told last year.
"I pledged at the general election that I'd fight to defend Swansea jobs in the Brexit negotiations, support rail electrification and building the Lagoon. These enquiries will put the Government in the spotlight to help deliver those pledges and to bring investment and jobs to Swansea."