UPDATE 1-Elan to delist in London, stay in Dublin, New York

* Says low trade volume did not justify cost

* Does not see impact on trading or liquidity from change

* Effective from Aug 10

(Adds quotes, background)

DUBLIN, July 10 (Reuters) - Irish drugmaker Elan Corp ELN.IELN.LELN.N said on Friday it would delist from the London Stock Exchange due to low volumes but retain its primary Dublin listing and a presence on the New York Stock Exchange.

Johnson & Johnson JNJ.N said this month it had agreed to pay $1 billion for an 18.4 percent stake in Elan, also acquiring a major stake in Elan's portfolio of experimental drugs to treat Alzheimer's disease.

“Having regard to the low volume of trading in the company’s ordinary shares on the London Stock Exchange, the benefits of the London listing are minimal and the cost of its maintenance is no longer in the interests of Elan shareholders as a whole,” Elan said.

As well as its primary listing on the Irish Stock Exchange, Elan will nevertheless retain its listing on the New York Stock Exchange in the form of American Depositary Shares, it said.

“It is not expected that the change in listing will have any material impact on trading or liquidity,” it added. “This change is due to be effective on 10 August, 2009.”

Reporting by Andras Gergely