* Knight Vinke says Darty not showing any urgency
* Darty likely to miss lower end of FY profit expectations
* Acting CEO sees no pick-up in markets in 2013
* Q3 revenue down 2.5 pct, like-for-like sales down 0.5 pct
* Shares down 6.5 percent (Adds detail, recasts lead, acting CEO, analyst comments, shares)
By James Davey
LONDON, Feb 15 (Reuters) - The biggest shareholder in Darty , Europe's No. 3 electrical goods retailer, demanded a seat on the firm's board after it issued a profit warning that threatens its final dividend.
Activist investor Knight Vinke, which owns 25 percent of Darty's equity, said on Friday it would exercise its contractual right to join the Darty board with immediate effect.
"It has taken more than six months for the board to implement the strategic changes we recommended back in July and we fail to note any increased sense of urgency in its deliberations, despite a deterioration in the trading environment that was not unexpected," Knight Vinke said.
Darty, which trails market leader Media-Saturn and No.2 player Dixons Retail, said sales trends had softened in January.
It said if current trading conditions continued it would miss the lower end of expectations for underlying pretax profit in the year to April, of 30 million euros ($40 million).
Darty, which made a 59 million euros profit in 2011/12 and has been battling weak economies and intense competition from online retailers, said most European markets had become even more promotional since January, particularly Holland and Spain.
"When you look at the overall euro zone data announced yesterday, we can't expect any material improvement in the coming year, and I think there will continue to be pressures," acting chief executive Dominic Platt told reporters.
"The consumer is tightening its belt in difficult circumstances and responding perhaps more to promotional activity."
Official EU data on Thursday showed the euro zone slipped deeper than expected into recession in the last three months of 2012 after its largest economies, France and Germany, shrank.
In December Darty paid an interim dividend of 0.875 cents and said it intended to maintain last year's full-year payout.
However, analysts think it could now be trimmed.
"The dividend is now uncovered (by earnings) and the new CEO might decide to cut it," said Panmure Gordon analyst Philip Dorgan, who slashed his current year pretax profit forecast from 42 million euros to 27 million euros.
Earlier this month Darty named Regis Schultz as its new CEO. He will join on May 1 from French furniture and electricals chain BUT, succeeding Thierry Falque-Pierrotin who stepped down in December.
His departure was prompted by an investor rebellion over executive pay that saw more than half of Darty's shareholders vote against the firm's pay report.
Schultz' task is to steer a turnaround plan, outlined in December, that will see Darty focus on its profitable businesses in France, Belgium and the Netherlands and try to eliminate losses at non-core businesses in Spain, the Czech Republic and Slovakia.
The firm is targeting net operating cost savings of 20 million euros a year within three years and expects surplus property disposals to raise 35 million euros of net proceeds.
Darty said total revenue in the 13 weeks to Jan. 31, its fiscal third quarter, fell 2.5 percent, with sales at stores open at least a year down 0.5 percent.
Gross margin was down 110 basis points, reflecting price cuts and low margin products, such as tablet computers, representing a greater proportion of the overall product mix.
Like-for-like sales rose 0.4 percent in Darty France, the group's main business, but slumped 13.4 percent in the firm's developing business division comprising Darty Turkey and Darty Spain.
Last February the group, formerly known as Kesa, sold its Comet business in Britain to private investment firm OpCapita. Comet has since closed down. In November, Darty sold its Italian business.
Darty shares were down 6.5 percent to 46.45 pence at 1025 GMT. ($1=0.7495 euros) (Reporting by James Davey; Editing by Mike Nesbit)