If you are in any doubt as to how serious the latest British assault on the America’s Cup is, there is one simple way of appreciating the effort and commitment that is going in to bringing the Cup back to Britain – just take a look at Ben Ainslie Racing’s base.

With the building now entering the final months of fit out, the striking 28m tall structure on Camber Quay in Portsmouth is impossible to miss.

Admittedly it’s still a building site and clearly you won’t get access, but you don’t need to in order to get a feel for how big an undertaking this building and the Cup campaign really is. Simply arrange your day to have lunch at The Still & West pub opposite the new BAR base and you’ll have a great view of the works.

Fortunately I was taken a step further last week and given a guided tour of the building.

In 13 years of covering the modern America’s Cup I have seen and been inside of plenty of impressive America’s Cup, bases but this one is something very different. The size of a shopping centre, the BAR base is no temporary structure designed for a couple of years’ lead up to the 35^th AC in 2017, this building is here to stay. Not only that, but the building itself has presented some interesting technical challenges, not least catering for the giant openings at the front. Here three huge three storey high bays each have a crane running on girders inside the building that can carry up to 30 tonnes each.

According to project manager Richard Pelley of Allied Developments, the building needs to withstand each of these cranes being brought to a halt at the same time with their full load 90 tonnes in place. Preventing the building from twisting, with such a large opening at one end has been quite a challenge apparently.

One of the bays in which hulls and wings will be craned in. The glass atrium above allows light to enter down the centre of the building but also allows those in the offices above to see what is going on below.

Looking down into the bays from the public gallery.

What will be the gym

The VIP floor provides a superb view of the harbour but also the race area and will be used for the first ACWS event of 2015.

Laying the floor for the visitor centre. The I beams with their circular cut outs are particularly unusual and help reduce the all up weight of the building while also allowing the building’s pipe work and services to pass through them rather than being led under the floor.

Looking north towards the IOW ferry terminal and Gunwharf Quays from the impressive triangular section stairwell. Allowing the building to heat up through the glazing while then keeping the heat in with insulation and then cooling it with the solar powered air conditioning has been a challenge too.

On the roof of the building looking north to the Spinnaker Tower