Key to a successful Brexit is to unlock growth potential across UK, says BCC

Securing a solid Brexit deal will be key for the U.K. but as the country heads into a General Election, British politicians shouldn't lose sight of the domestic issues facing the economy and its businesses, a business lobby group has warned.

"You could have the best Brexit deal in the world, (however) it's not worth very much if your domestic economic conditions, if the fundamentals for business in (the U.K.) aren't as good as they could be," Adam Marshall, director general of the British Chambers of Commerce, told CNBC Tuesday.

"For any business person out there who's had a mobile phone signal dropped, or poor broadband or can't recruit the people they need – these are the things that you solve at home, they're not things you solve through a Brexit deal," Marshall added.

On Tuesday, the British Chambers of Commerce (BCC) launched a manifesto for the upcoming General Election, which called upon the next government to not only offer answers to businesses that have questions on Brexit, but also provide coherent, strong strategies when it comes to supporting economic growth on a local, regional and national level.

To coincide with the manifesto launch, the lobby group outlined a number of key priorities it wanted the next British government to address and commit to, including no new upfront taxes on businesses during the course of the next parliament.

Other demands mentioned include the ability to deliver "frictionless future trade arrangements" with the European Union; make sure U.K.-based firms have access to "world-class digital infrastructure"; and that a new U.K. regional funding system was established.

"I think all the political parties need to accept that they're going to have to manage Brexit, but if they're not managing the United Kingdom effectively, whilst they're dealing with Brexit, then we'll never ever make a success of it," Marshall said on CNBC's Squawk Box Europe.

Less than a month after the U.K. officially began its divorce proceedings with the EU, Prime Minister Theresa May surprised markets in April by calling for a General Election on June 8, 2017.

According to Reuters, three recent opinion polls show that while the Prime Minister's Conservative party still retains a strong lead, the U.K.'s opposition party Labour, has shown a rise in popularity as of late.

With the upcoming U.K. election expected to define the conditions of the U.K.'s exit from the EU; negotiating a strong deal with the EU has been a popular topic of discussion for U.K. political parties in the run up to the election.

However, in a statement released along with the manifesto announcement, the BCC director general said at this election, business groups were looking for "a clear commitment from all parties to create the best possible conditions for growth" across the UK. The manifesto added that the election "cannot and must not be just about Brexit."

While uncertainties linger over what the U.K. will look like in a post-Brexit world, the BCC emphasized that "action is needed" on a whole host of domestic topics, such as assisting local growth and improving the competitiveness of Britain's business environment.

"While businesses all across the UK want a good Brexit deal, they are very clear that decisions taken here at home matter as much – if not more – to our future growth prospects," Marshall said in a statement.

"The key to a successful Brexit – and future economic growth – is to do everything to unlock the growth potential in our towns, cities and counties."