After more than a year of planning, organisers of the Elton John concert are bracing themselves for the final week, which the project manager has described as a “military operation”.

Work on next Saturday’s (May 29) concert started more than 12 months ago but the heavy machinery will start rolling into Vicarage Road from Monday as all the preparation starts to come together.

Paddy Flavin was made redundant by Watford in April last year but head of operations Glyn Evans decided to bring Flavin back to assist with the concert on a consultancy basis due to his experience in helping to organise the former chairman’s last performance at Vicarage Road in 2005.

Flavin explained: “There will be five days of artics coming in and there is a production schedule where everything works to the hour.

“If that is not complied with then you could have some real problems on your hands so it is quite a military operation from next Monday.

“There are lots of agencies we are working with to set up six hours of concert on one day, for one person – it is quite amazing really. That is the power of somebody who is an icon.

“But there will be nearly 20,000 people here having a great time and that is what it is all about.”

The amount of time and effort that has gone into the concert has been quite staggering – for example it has taken around eight months just to have the stadium plan signed off.

Every temporary structure has to have the exact calculations documented and approved by the Safety Advisory Group, who are now in dialogue with the club on a daily basis.

The task is made considerably more difficult due to almost 9,000 extra seats being installed on the pitch as additional turnstiles, toilets, signage and flooring is needed.

Work has been taking place this week in preparation, including seats in the Lower Rous being taken out to make space for disabled ramps.

Flavin explained that although the stadium is capable of hosting concerts, there are a number of issues and problems which must be addressed, ranging from the East Stand roof to needing fire certificates for the drapes in the changing rooms.

The East Stand roof has been deemed unsafe so a crash deck has been installed, every contractor needs public liability insurance and there are different laws for hosting concerts compared to sporting events.

Matters were made more difficult by the fact that until May 8, it was unclear whether Saracens would be playing a semi-final at Vicarage Road last weekend.

Evans said experiences from the 2005 concert have helped immensely but explained that everything still needed to be started from scratch as the stadium layout has changed and the stage is a different size.

He estimated the club will spend around £600,000 on the concert and the stage alone will cost £78,000.

Two thousand emails from 46 different contractors gives an indication of the scale of the challenge in hosting the event.

But Evans said: “We have harnessed a lot of skills which we have within the club to be able to put this together and the mortar in the bricks of this has been Paddy as the project manager.

“And we continue to do the day job which is quite incredible in a restructured business with less hands.

“It has been hard work but the benefit will be that we raise money for players, that is the critical thing.”

The pitch was this week stripped of all its grass and special panelling called Super Track will be used as flooring.

Security guards will be employed to protect the equipment at night during the next week and Upper Occupation Road will effectively be closed from Monday.

Immediately after the event all the sound equipment will be packed up and sent to the next destination and Flavin expects everything at Vicarage Road to return to normal by June 2.