The 50-year-old Spaniard replaced Steve Clarke, sacked last month after a 1-0 defeat by Cardiff City left Albion two points off the relegation places.

But, under caretaker manager Keith Downing, the Baggies are currently four points above the bottom three.

Mel himself was sacked by Betis last month, with a 4-0 defeat by local rivals Sevilla helping seal his fate as the club failed to make good on last season's seventh-placed La Liga finish which took them into the Europa League.

Previously in charge of Rayo Vallecano, Mel was appointed by Albion on a relatively short 18-month contract, but the Midlands side's sporting and technical director, Richard Garlick, told the club's website: "I'm delighted to welcome Pepe to the club.

"His appointment concludes an extensive recruitment process during which we have cast the net far and wide to identify the most suitable candidate to take the club forward.

"Pepe was a strong contender from the outset due to his impressive achievements and has emerged as our number one candidate.

"He is a forward-thinking coach whose teams are renowned for playing an attractive and positive style of football."

Downing will remain charge for Saturday's match away to Southampton, with Mel watching from the stands before taking charge of his first match as Baggies boss in the home game against Everton at The Hawthorns a week on Monday.

Under Downing, who will remain on the staff, the Baggies took six points from four unbeaten league games.

"The board is extremely grateful to Keith, the coaching staff and players for their efforts over the past month, said Garlick.

"Keith will have an important role to play in supporting Pepe as he coaches in England for the first time."

Last month, the BBC reported talks had broken down between Mel and the club over the issue of backroom staff, with the coach wanting to bring in his own assistants while Albion insisted the likes of Downing remained in place.

"We have identified suitable candidates to work within our existing structure," Garlick said at the time.

West Brom will hope Mel can achieve similar success to that enjoyed by another former Liga manager, Mauricio Pochettino, at fellow Premier League club Southampton.

The Argentinian, who had been in charge of Espanyol, also had no track record in English football when he arrived at St Mary's in January last year but, under his guidance, the Saints are now an impressive ninth in the table.