The Hornets are joint-second highest scorers in the Championship this season, with Matej Vydra and Troy Deeney scoring 16 of their 38 league goals.

Clarke worked with Vydra at West Brom, and although the Czech forward missed large spells with a hamstring injury, the new Royals boss was impressed with what he saw.

“I had Vydra at West Brom for six months,” he said. “He didn't get too many chances as he pulled a hamstring early in the season and by the time he recovered from that I was on my way out.

“But was a good boy to work with though, a terrific guy with a good attitude and good qualities in training.

“Troy Deeney has also been an excellent player in the Championship for years. I’m surprised no one has come in from the Premier League and given him a chance.”

He continued: “Watford is actually one of the teams I watched quite a few times when I was out of work. They’ve got a strong squad and spent a lot of money trying to get out of the divison.

“They’ve got quality everywhere, especially the Scottish international Ikechi Anya who is really quick, direct and can cause you problems.

“We’ll have to be at our best to get something out of the game.”

Clarke took his first training session on Thursday morning and a big boost for Royals fans is that Jem Karacan and Danny Guthrie both came through unscathed.

Neither will be involved this weekend but Guthrie could play a part in Reading’s trip to Brighton on Boxing Day.

It was a short, sharp session from Clarke and he was delighted to be back out on the training ground.

“I loved walking out there today,” he beamed. “It’s been a long time since I’ve had my boots on. I was setting up the exercises for the first-team squad before they were out and I could see the Under 18s and Under 21s training which felt great.

“The players were great. The attitude and quality, application and concentration on the training session was top class and long may that continue.”