Buckingham has twice walked off the project because of the client’s failure to pay money owed and is now seeing legal redress. The case hits the courts this week.
The action is against its client, County Development Northampton Limited (CDNL), the project vehicle set up by Northampton Town chairman David Cadoza.
HM Revenue & Customs has also issued legal proceedings against the club for outstanding
Buckingham Group Contracting Limited issued a full statement setting out the troubled history of the Sixfields stadium project, which was originally conceived by 1st Land Ltd before being taken over by CDNL.
Buckingham’s statement says: "In order to assist Northampton Town Supporter's Trust in their efforts to deliver accurate information to Cobblers supporters we would like to point out that our Contract with 1st Land Ltd to build the replacement East Stand at Sixfields was valued at £4.151m.
"The structure which we have been building is not the original scheme designed by RMJC Architects and permitted by the Borough Council on 28th November 2013 under Planning Application N/2013/1048. This original scheme incorporated conference facilities, a banqueting suite with ancillary corporate hospitality facilities, new kitchens and a gymnasium.
"Buckingham's earliest involvement at Sixfields was in January 2014 when we were asked to produce a budget price for this original scheme which was going to cost in excess of £8m to build and fit out. This original scheme represented a total transformation of the football club's facilities and as club chairman David Cardoza said at the time 'would take the football club into the 21st Century'.
"The decision to abandon the original scheme and replace it with a bog-standard spectator stand came exclusively from the football club via the club's project managers – Jemmerley Ltd – in an email dated 17th April 2014, and Buckingham signed a JCT Contract with 1st Land Ltd on 1st May 2014 to build the amended design for the replacement East Stand at a contract value of £4.151m.
"The football club had already entered into an arrangement for 1st Land Ltd to act as main contractors for the overall re-development package at Sixfields. The overall package included some upgrading work to the flood-lighting and some relatively minor works within the West Stand
"The value of the main contract which the football club awarded to 1st Land Ltd was £8.2m.
"1st Land Ltd made three payments under their contract with Buckingham between 1st May and 14th July 2014. These payments totalled £441,917 net of VAT. These are the only monies Buckingham have ever received for works carried out and certified to date on the East Stand.
"When we pulled off site in September 2014 we were owed a total of £1.852m by 1st Land Ltd. We pursued Mr Grossman for payment up until the beginning of December 2014 when we commenced administration proceedings against 1st Land Ltd.
"At the end of March 2015 Buckingham reached agreement with David Cardoza to return to Sixfields to recommence work on the East Stand. This agreement was based on repeated assurances received from Mr Cardoza that there were adequate, additional loan monies which remained available to draw down from the Borough Council to fund the completion of the East Stand works.
"We signed a new JCT Contract to complete the East Stand with County Developments (Northampton) Ltd [CDNL] and returned to site to resume work on 13th April 2015. Under this new contract CDNL also accepted liability to pay Buckingham the £1.852m debt owed by 1st Land Ltd, no later than 31st December 2015.
"The first payment to Buckingham under the new contract with CDNL was due on 8th May 2015 but was not forthcoming. On 20th May 2015 we issued a formal notice to suspend works on the grounds of non-payment.
"We wish to make it clear that the reason why the East Stand construction works ceased completely in early June 2015 was entirely due to non-payment of monies due and certified. The cessation of works had nothing whatsoever to do with any purported proposals from any prospective investor with plans to re-design the stadium. We stopped work because we were not paid.
"For the avoidance of doubt we have not been paid a penny by CDNL. CDNL are liable to Buckingham for circa £2.989m for works completed and certified on the East Stand, and for the debt that CDNL took over from 1st Land Ltd, which is why we are pursuing a winding up order against CDNL in the High Court this Thursday 22nd October 2015."
Northampton Town chairman David Cardoza said that he was “working night and day to secure a resolution to all of the issues that the club are facing at the moment”.