A series of leaked emails between key figures in Ukip reveals growing chaos at the heart of the party as it struggles to fill a policy vacuum just days before crucial local elections in which it is expected to make spectacular advances.

In one email, a senior party figure claims that leading the anti-EU party is like "herding cats". Ukip leader Nigel Farage is warned that his party is facing a decade without credible policies, as crippling internal rows rage, and it is suggested that the party should consider buying off-the-shelf strategy from right-leaning thinktanks.

Senior members must "get off their hobby-horses" if the party is to develop policies, Farage is told in the bombshell emails from Stuart Wheeler, the party's treasurer, and Godfrey Bloom, a leading Ukip MEP.

A despairing Bloom, writing last Thursday, warns: "My experience thus far is that as soon as more than two people get in a room progress completely stops. Even where we have experts of our own, they disagree." Bloom suggests the party should now consider buying policy "off the shelf" from thinktanks to lend it some credibility rather than attempting to "reinvent the wheel" by devising party positions on the major issues of the day.

Wheeler, a former Tory donor who gave £5.5m to the Conservatives in 2001 before being expelled for also donating to Ukip, responds: "I could not agree more strongly that some people will have to get off their hobby-horses."

Details of the party's internal crisis are revealed today as Ukip prepares to field an unprecedented 1,217 candidates in Thursday's local elections. The party is unlikely to return large numbers of councillors but Downing Street fears it will deprive the Tories of victory in many seats and be the cause of major trouble for David Cameron's leadership.

Along with its strong anti-European Union message and calls for a hardline on immigration, Ukip is campaigning heavily on issues likely to appeal to wavering Tories, including opposition to green belt development, wind farms and a second high-speed rail line. However, the party's manifesto is vague on details as it attempts to appeal to the broadest audience, including disaffected Labour and Liberal Democrat voters.

The emails leaked to the Observer illustrate how powerless the party is to build a manifesto as it attempts to please its politically divergent support. Bloom says the party's policies are "naturally coming under more scrutiny" as it grows, but warns Farage of the inability of members to agree on policy lines.

Bloom, who also complains that whatever the party says on tax and the economy will "be sneered at or decried", writes: "The charm and frustration of Ukip is we have doctors who fancy themselves as tax experts, painters and decorators who know all about strategic defence issues and … retired dentists who understand the most intricate political solutions for the nation.

"Our website will have no policies at all on there for 10 years if we adopt a neo-Byzantine approach to formulating them. This means some quite senior members are going to have to stable their hobby-horses."

The former financial economist also reveals a split between the old stalwarts of the party, formed in 1993 in response to the Maastricht treaty, and the new members who he fears are introducing "political correctness" among other "main party baggage". Ukip is said to be picking up 1,000 extra members a month, with membership now exceeding 25,500. Bloom writes: "Having worked on the defence paper for over one year it would appear Ukip has more military and naval experts than we have soldiers. Most of them do not agree with each other. It is like herding cats. We are also attracting new members who bring main party 'baggage'. Focus groups, quotas, even political correctness.

"We must be wary of listening to these siren voices. We did not get where we are today by following, but leading."

Bloom claims that he has been in talks with two free-market thinktanks, the Institute of Economic Affairs, and Civitas, whose policies he suggests "buying off the shelf where it is close to our own small government, low tax, libertarian position".

The Ukip MEP, who admits in the emails that his party "do not have the resources to write serious papers on major subjects", adds: "If Nigel, or indeed any of the 'frontbench' spokesmen talk of welfare or tax, the endorsement of such institutions is a very strong shield from the sort of dismissive left wing interviewers with whom we usually cross swords.

"Imagine Nigel in a hostile (oh yes it will be) interview with a 'Paxman', being able to say "Yes it will work, our policy has been completely vetted and endorsed by........" fill in the blank, Civitas, IEA, IOD, BMA, RCN etc..."

Wheeler, who reportedly made a £90m fortune in investment banking, writes that he agrees with "a great deal" of Bloom's points, but adds that the party's "policies must be Ukip's policies". He adds: "Obviously we cannot just say, when asked about what our policies are, that we agree with the IEA on X, Y and Z, and agree with Civitas on A, B and C, and some other thinktank on others etc."

A spokesman for the party said: "What you are seeing is discussions about policy development. Mr Bloom would like to get things done rapidly, Mr Wheeler would like to ensure that consensus is reached.

"It merely displays creative tension that in the end will produce a far better policy platform than we might have otherwise without due discussion."

The emails

The email conversation revealed between Godfrey Bloom, the Ukip MEP, and party treasurer Stuart Wheeler:

From: Godfrey Bloom

Sent: 25 April 2013 10:29

To: Stuart Wheeler, Nigel Farage and others

It would appear Ukip has more military and naval experts than we have soldiers. Most of them do not agree with each other. It is like herding cats.

From: Godfrey Bloom

Sent: 25 April 2013 10:29

To: Stuart Wheeler, Nigel Farage and others

We are also attracting new members who bring main party 'baggage'. Focus groups, quotas, even political correctness. We must be wary of listening to these siren voices. We did not get where we are today by following, but leading.

From: Godfrey Bloom

Sent: 25 April 2013 10:29

To: Stuart Wheeler, Nigel Farage and others

We do not have the resources to write serious papers on major subjects, why reinvent the wheel? Why not buy policy 'off the shelf', where it is close to our own small government, low tax, libertarian position.

From: Godfrey Bloom

Sent: 25 April 2013 10:29

To: Stuart Wheeler, Nigel Farage and others

Now here's the rub. My experience thus far is that as soon as more than 2 people get in a room progress completely stops. Even where we have experts of our own they disagree.

From: Godfrey Bloom

Sent: 25 April 2013 10:29

To: Stuart Wheeler, Nigel Farage and others

The charm and frustration of Ukip is we have doctors who fancy themselves as tax experts, painters and decorators who know all about strategic defence issues, and branch chairmen, retired dentists, who understand the most intricate political solutions for the nation.

From: Stuart Wheeler

Sent: 25 April 2013 13:38

To: Godfrey Bloom

Dear Godfrey, I could not agree more that some people will have to get off their hobby-horses.