The adviser trade body has warned on the state of negotiations over Britain's departure from the European Union, and said adviser's clients will lose out if a good deal for financial services isn't secured.
John Barrass, the deputy chief executive of the Personal Investment Management & Financial Advice Association (Pimfa), criticised politicians for a "marked and arguably regrettable disregard" for the fact 80 per cent of the UK's GDP came from services, of which the financial services sector was the biggest part.
He said: "They have made a half-hearted stab at dealing with this with the vague 'enhanced equivalence' concepts in the White Paper, but there is a long way to go before these become a broad-based and enforceable framework for business operations."
The government has previously said the passporting regime, which allows firms to do business across the EU, will not apply after Brexit but it has called for "enhanced equivalence", another model that would allow companies to sell their services throughout the bloc - a proposal the EU itself has rejected.
Mr Barrass said even if the government's proposals became reality, advisers and their clients appeared unlikely to be included.
He said: "All nations are jealous to protect their citizens, so in the dismantling of the systems for cross-border financial services access the first to go are the mechanisms that help firms to assist private clients in investing their money wisely and effectively.
"Conversely, in the replacement of those systems by some new device the individual and family, and the cross-border means to help them, are the last to be considered. Sometimes they never are.
"So the result of all this is that whatever happens with Brexit, the part of the financial services industry most concerned with helping individuals and families, who are most likely to be adversely affected if the Brexit process goes wrong, is the one least likely to benefit from measures to mitigate any costs."
Mr Barrass said any British firms which have clients in other EU states, including UK expatriates, would have to develop new entities in other EU countries to keep access to them.
He added: "That will cost and the clients will have to pay - not a good start for a new, globally competitive UK.
"Meanwhile access to products such as funds for retail investment, or to continental exchanges to trade EU equity, will also be more difficult; this will put new sand into the works and risk piling up the extra payments clients will have to make."
Last month the government confirmed European rules - including those governing the financial services sector - will continue to apply to the UK until the end of 2020.
In March the UK and the EU reached an agreement for a 21-month transition period in order to negotiate a final trade deal.
This will mean that while the UK formally exits the EU on 29 March 2019, the transition will run until the end of December 2020 and European law will apply throughout this period.