LONDON - The United Kingdom leaves the European Union at 2300 GMT on Friday but Prime Minister Boris Johnson has a bulging to do list for what he has cast a "new dawn" for the country.

Below are the biggest issues he has to deal with.

TRADE

As soon as the United Kingdom formally leaves the EU on Jan. 31 it can start negotiating trade deals with other countries.

The European Union - which accounts for about half of the United Kingdom's trade - along with the United States are the government's top priority for securing new trade deals. 

A sticking point in U.S. talks will be a British proposal for a unilateral digital services tax, despite a U.S. threat to levy retaliatory tariffs on British-made autos.

'DIS-UNITED KINGDOM'

Brexit strained the bonds which tie the United Kingdom together: England and Wales voted to leave the EU but Scotland and Northern Ireland voted to stay.

Scottish nationalists are pushing for an independence referendum which Johnson says he will not allow. Irish nationalists also want a referendum on uniting Ireland.

TRUMP AND CHINA

Johnson granted Huawei a limited role in Britain’s 5G mobile network on Tuesday, frustrating a global attempt by the United States to exclude the Chinese telecoms giant from the West’s next-generation communications. 

It is unclear what impact the decision will have on relations with the Untied States - the United Kingdom's closest ally. China has also cautioned the United Kingdom for what it says is meddling in Hong Kong - its former colony.

'ECONOMY, STUPID'

Ahead of the December election, Johnson said he would spend more on the National Health Service, infrastructure and ensure prosperity across the United Kingdom. In translation, that means more borrowing: more UK government bonds sold.

Some businesses are reporting a post-election "Boris bounce" recovery, and finance minister Sajid Javid says he is hopeful that Britain's economic growth can eventually bounce back to its pre-financial crisis levels of nearly 3% a year. 

LONDON FINANCIAL CLOUT

Britain's vast financial services sector's future access to the European Union's will be one of the first issues to be discussed and must be finalised by the end of June.

The finance industry want to maintain a close relationship with the EU but it will not enjoy the same level of access as under the bloc’s single market, which includes a so-called passporting regime.

Instead, the government will be looking for the EU to make ruling based on equivalence where each side decides if the other’s rules for financial stability and investor protection are sufficiently aligned with its own to grant access.

The EU has indicated it will use the threat of restricting access for Britain's biggest export industry as leverage for wider demands such as fishing access to UK waters.

IRAN

While London has repeatedly said it wants the nuclear deal with Iran to succeed despite Trump's abandonment of the pact, Johnson has called for a new Trump deal to replace it.

As the United Kingdom forges a post-Brexit foreign policy, Iran could give the best indication of its future orientation: will Johnson ultimately side with the United States or keep the United Kingdom aligned with the EU's Germany and France

NEW TEAM

After Brexit, Johnson is planning a reshuffle of his cabinet team of top ministers.

(Reporting by Guy Faulconbridge and Andrew MacAskill; Editing by Alison Williams) ((guy.faulconbridge@thomsonreuters.com; 07825218698;))