Watford are dismayed at Tottenham's request to play their Carabao Cup match in Milton Keynes and warned the "integrity" of the competition is in jeopardy.
Discussions are underway between the EFL and Watford, with the league expected to agree to Spurs' plea to play their Carabao Cup third-round fixture at Stadium: MK - the home of MK Dons - at their board meeting next Thursday.
Spurs' new stadium will not be ready in time while Wembley, where they are currently playing Premier League fixtures, will not be ready either - and Sky Sports News understands Watford are disappointed that the League Cup game has therefore not been moved to Vicarage Road.
A Hornets source told Sky Sports News: "The integrity of the competition should stand above everything else. If Tottenham cannot fulfil the fixture, then we believe it should be reversed."
Both boardrooms will have the chance to discuss their concerns when Watford welcome Spurs to Vicarage Road in the Premier League this Sunday, live on Sky Sports - a match that Watford agreed to switch to their home ground back in June while Spurs new 62,000-seater development is finished.
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In a statement, Spurs said: "The club felt it would not be beneficial to request a reverse of the fixture as it would have resulted in no more than a 10 per cent allocation of tickets for our supporters at the venue of our opponents.
"In contrast, we shall have a ticket allocation of up to 90 per cent at a neutral venue, ensuring greater access for our fans."
Stadium:MK in Milton Keynes was a potential home venue for Tottenham before they secured Wembley for the entirety of last season as the new Tottenham Hotspur Stadium's construction began.
The ground suffered a setback over fire safety concerns earlier this month and Spurs, who have won all three of their opening Premier League games, still do not have a set date to move into their new stadium.