London(CNN) British Prime Minister Theresa May has defended her Brexit plan and insisted that the UK will be able to strike new trade agreements with the rest of the world after it leaves the European Union.
May's comments come after US President Donald Trump added himself to the chorus of skeptics doubting her proposal -- saying it isn't clear if the agreement will allow a US-UK trading partnership.
"I think we have to take a look at seriously whether or not the UK is allowed to trade. Because you know, right now, if you look at the deal, they may not be able to trade with us," Trump said on the White House's South Lawn.
However, on a stop in Wales while selling her deal around Britain, May reiterated that the plan "clearly identifies" that the UK will have an independent trade policy, and that it had already begun discussions with Washington.
"We will be able to do trade deals with countries around the rest of the world," the Prime Minister said on Tuesday.
"As regards the United States, we have already been talking to them about the sorts of agreements that we could have in the future. We have a working group set up ... which is working very well (and) has met several times and continuing with the US on this."
Trump said Monday the prospect that the plan could limit the UK's ability to trade with the US after it exits the EU on March 29, 2019, "wouldn't be a good thing."
"I don't think they meant that. I don't think that the Prime Minister meant that. And hopefully, she'll be able to do something about that," Trump said.
All 27 remaining European Union leaders approved Britain's Brexit agreement on Sunday but May is yet to convince UK Parliament to sign off on the deal.
Following the 2016 referendum, then-candidate Trump was a vocal cheerleader of the proposal to extricate the UK from the bloc, even going as far as predicting people would call him "Mr. Brexit" for his support.
The British Parliament will have a "meaningful vote" on the Withdrawal Agreement from the European Union on December 11, a Downing Street spokesman told CNN on Monday.
Under the draft agreement, the UK will stay inside the bloc's single market and remain subject to EU laws and regulations until the end of December 2020 while the two sides attempt to iron out a new trade relationship.
During this period, all existing EU "regulatory, budgetary, supervisory, judiciary and enforcement instruments and structures" will continue to apply within the UK, including rulings made in the Court of Justice of the EU.
Following unanimous approval of the deal by Europe's 27 remaining members, May is currently scrambling to sway votes for the agreement in Parliament.
May has not said what would happen in the event Parliament rejects the deal, but she's insisted that there is no better Brexit deal for Britain.
"I can say with absolute certainty that there is not a better deal available," May said.
Multiple voices from both sides in the UK's referendum on EU membership in 2016, both Remain and Leave, have expressed opposition to the agreement.
Objecting to May's draft political declaration -- which covers future relations on trade, security relations and other issues -- opposition Labour leader Jeremy Corbyn said it was "26 pages of waffle," while Boris Johnson, a chief architect of Brexit and a former foreign secretary who resigned from May's Cabinet over her plans, said it "makes a complete nonsense of Brexit."
Ahead of the vote, May asked MPs to "consider the interests of this country, the interest of constituents, and consider the importance of delivering on Brexit."
On the question of Gibraltar, Britain's tiny territory on the south coast of Spain, May said that, having worked "constructively" with the Spanish government, the UK has ensured Gibraltar will be covered "by the whole Withdrawal Agreement and implementation period."
"We will always stand by you, we are proud that Gibraltar is British," May added.
Recognizing the "depth of concern" some MPs may still have in relation to the so-called "backstop" on the Irish border, May said it was "an insurance policy no one wants to use."
Should no other solution be found before the end of the withdrawal piece, the "backstop" would come into effect, consisting of a "single customs territory between the (European) Union and the United Kingdom."
That customs union would remove all tariffs, checks on rules of origin and quotas, and would cover all goods except fishery products. "To this end, the United Kingdom will harmonize the commercial policy applicable to its customs territory with the common commercial policy of the Union," the agreement says.
"Put simply, there is no deal that comes without a backstop, and without a backstop there is no deal," May told Parliament Monday.