Astaire Secs, formerly Blue Oar, fined by LSE

* Fined 225,000 pounds for breaching AIM rules

* Broke rules in relation to Managed Support Services

* LSE says it failed to adequately assess company

* Astaire shares indicated down 5 percent by 0718 GMT

LONDON, June 22 (Reuters) - Astaire Securities (ASTR.L), the stock broker which was known as Blue Oar until it changed its name earlier this month, has been fined by the London Stock Exchange (LSE.L) for breaching the rules of the Alternative Investment Market (AIM).

The London Stock Exchange fined the company 225,000 pounds ($370,800), saying on Monday that it had breached the AIM rules in relation to its conduct as nominated advisor to an AIM company, Managed Support Services (MSPS.L), previously known as Worthington Nicholls Group.

Astaire's share price was indicated down 5 percent by 0718 GMT.

In December 2007 Worthington Nicholls saw its shares plunge 11 percent after it announced that writedowns of assets would be more than double what it had been expecting, following an accounting investigation.

The LSE said Blue Oar failed to adequately assess Worthington Nicholls, failed to carry out appropriate due diligence, failed to advise the company regarding its statements, and failed to liaise properly with the exchange.

"It is essential for maintaining investor confidence that these responsibilities are properly fulfilled before and after an admission to AIM," said Nick Bayley, Head of Trading Services in a statement.

It is the first time that the exchange has issued such a fine this year. Last year it fined Meridian Petroleum MRP.L 75,000 pounds for breaching AIM rules. [ID:nL19178972]

AIM is the LSE's junior market, designed for smaller and emerging companies. Its lighter regulatory touch was intended to attract companies which might not be able to afford a full LSE listing.

But it has faced calls for tighter regulations to protect investors.

In February last year, the LSE introduced a new rule book for nominated advisers, the city brokers that bring companies to AIM, setting out their duties and responsibilities.

Astaire said in a statement: "Astaire Group welcomes the fact that this matter has now been brought to a conclusion. The company gave its full co-operation to the exchange during its investigations and has accepted the exchange's findings." (Reporting by Ben Deighton; Editing by Rupert Winchester)