UKIP's turmoil in Scotland deepened last night after the right-wing anti-immigrant party suspended five senior members from its approved list of candidates.

The individuals - including the former Scottish leader and chair - are critics of party MEP David Coburn, prompting accusations of "control freakery".

UKIP was last week rocked by allegations of sexual harassment against party general secretary Roger Bird, who was accused of making inappropriate suggestions to a potential female candidate.

However, a lingering row is also continuing to hamper the party north of the border.

Last year, six of UKIP Scotland's shortlisted candidates for the European election withdrew after believing a small clique of activists was planning a takeover.

The botched selection contest was eventually won by Coburn, who was later elected to the Brussels Parliament and became the party's first elected representative in Scotland.

Two of the six members have since quit the party, and the other four - Christopher Monckton, Mike Scott-Hayward, Paul Henke and Ross Durance - have now had action taken against them.

Matthew Richardson, the UKIP party secretary, recently informed the quartet that they could not be party candidates in future elections.

He wrote: "Having investigated your case in greater depth with the Party Chairman, he has taken the decision to suspend you as an approved candidate under 12.2.1 of the constitution as he considered that your withdrawal from the candidate list during the selection process for the European elections was disruptive to the Party and brought it into public disrepute."

Each member was told that "you are not therefore a suitable person to be a candidate for the Party in the future".

The fifth candidate curb was imposed on Donald Gatt for alleged "published comments" following the European selection contest.

Monckton, who used to front UKIP Scotland until he was sacked by party leader Nigel Farage, is believed to have arranged a meeting for the suspended candidates in Edinburgh today.

Scott-Hayward, a former party chair, told the Sunday Herald: "It is totally undemocratic and is totally out of line with the party's principles."

He added: "I consider that I failed in my tenure as their Chairman in that I did not achieve one of my objectives which was to alter the balance of membership away from the wilder and more extremist thinkers towards a greater number of sensible, right thinking folk who do indeed support UKIP's main policies."

His party membership lapsed in the last few days.

Henke, who has stood for UKIP eight times in elections, was previously suspended for 100 years by the party for speaking to the media.

This ban was lifted following a court challenge.

UKIP Scotland's current chair is Misty Thackeray, who was revealed by this newspaper to have accused Glasgow City Council as being for "Gays, Catholics [and] Communists".

He is now Coburn's chief of staff. One party source said of the suspensions: "It's about helping David and Misty. It's control-freakery."

A UKIP spokesman said: "It is a pity, but they wanted to be the message, rather than represent the party. They were divisive and had no concept of teamwork."

A spokesman for the Scottish Conservatives said: "UKIP is clearly not competent nor credible in Scotland. The party has consistently failed at by-elections, and binning five of its prospective candidates won't help that.

SNP MEP Alyn Smith said: "The ongoing shambles of UKIP in Scotland continues - at this rate they'll have no candidates left to stand in north of the border."