The U.K.'s main Brexit negotiator added that 95 percent of the U.K.'s withdrawal agreement is now settled, adding that the U.K. the EU had also "made good progress on the structure and scope of the future agreement."
The sticking point of how to treat the border between Northern Ireland, which is part of the United Kingdom, and the Republic of Ireland, which is a member of the European Union, had previously caused talks to stall.
Raab claimed in his letter that this issue is near to being resolved, for now, as both sides "agree on the principle of a U.K.-wide customs backstop."
The backstop would effectively keep the U.K. within European arrangements — such as the customs union and at least some parts of the EU's single market — should a free trade deal or technological solution to Ireland's border issue not have been found by the end of the transition period.
The customs union is an agreement that allows partaking countries to set common external tariffs, allowing goods to travel freely between those countries. The single market is a deeper form of co-operation between member states that allows the free movement of goods, services, money and people in the bloc.
On Tuesday, the ratings agency Standard & Poor's warned in a report that the U.K. economy could enter a recession should the country exit the European Union with a so called "Hard Brexit."
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