BRUSSELS — The long-awaited post-Brexit trade deal has been signed by EU heads.

Officially called the EU-UK Trade and Cooperation Agreement, it has taken months of negotiation to agree.

European Council President Charles Michel and European Commission President Ursula von der Leyen signed on behalf of the European Union on Wednesday morning.

It will now be flown to London by a Royal Air Force plane where Prime Minister Boris Johnson will sign for the UK in 10 Downing Street.

“The agreement that we signed today is the result of months of intense negotiations in which the European Union has displayed an unprecedented level of unity,” Michel said.

“It is a fair and balanced agreement that fully protects the fundamental interests of the European Union and creates stability and predictability for citizens and companies”.

European leaders have welcomed the deal, describing it either as a moment of "historical importance", an "important milestone", or a "major step forward".

But most have also reiterated warnings that despite the deal, changes to the current relationship will come into force on Jan. 1.

The signing of the deal on Wednesday comes ahead of British MPs and MEPs holding votes on whether to ratify the agreement.

The UK Parliament will start debating the agreement later on Wednesday setting up new trade rules between the 27-nation bloc and former member Britain.

The agreement eventually needs approval from Britain’s Parliament, and from the EU’s legislature, which is not expected to take up the deal for weeks.

The leaders of the European Parliament’s political groups said they would not seek full approval until March because of the specific and far-reaching implications of the agreement.

The overwhelming expectation is that EU lawmakers will approve the deal.

The 1,240-page post-Brexit deal was sealed by the EU and the UK on Christmas Eve, just a week before the year-end deadline.

Three separate agreements have been signed. Their full names are as follows:

1) Trade and Cooperation Agreement between the European Union and the European Atomic Energy Community and the United Kingdom of Great Britain and Northern Ireland.

2) Agreement between the European Union and the United Kingdom of Great Britain and Northern Ireland concerning security procedures for exchanging and protecting classified information.

3) Agreement between the Government of the United Kingdom of Great Britain and Northern Ireland and the European Atomic Energy Community for Cooperation on the Safe and Peaceful Uses of Nuclear Energy.

Two copies of each agreement will be signed. Once both parties have put their names to the documents, one of the two original copies of each agreement will be sent to the EU where they will go to the Archives of the Council and the other to the United Kingdom. — Euronews