Speaking exclusively to Express.co.uk, UKIP MEP Margot Parker warned Whitehall was allowing itself to be bullied by obstructionist EU negotiators.
Questioned whether she expects the summit to be a success, she said: “I don’t. I expect it to be more of the same.
“From the evidence so far, I don’t think Theresa May will achieve the breakthrough she is seeking.”
The EU lawmaker criticised the EU for aggravating the Brexit process, and accused the Government of failing to stand up to EU demands.
She said: “The ‘hard messages’ it sends out are an attempt to bully the Government and, in turn, the Government is allowing itself to be bullied.
“There is a lack of vision on both sides and with the EU waving a big stick at us I see little prospect of a reasoned debate.”
Questioned on what the Government should do if no breakthrough is achieved, she said: “We should simply tell the EU we will leave and adopt WTO rules.”
Ms Parker noted the likely stumbling blocks at the summit are the control of movement of individuals entering in the UK and the European Court of Justice, stating “both are unacceptable to most people”.
She added the amount of the money the UK is obliged to the pay the EU prior to its departure will also raise tensions, noting “taxpayers’ money could be spent more wisely”.
Ms Parker’s sentiments were echoed by independent MEP Nathan Gill, who said: “The likelihood of any significant develop at the June summit is slim given that it is clear the EU wants to continue to frustrate this issue while running down the clock.”
UKIP MEP Jonathan Bullock concurred with Mr Gill’s statements, adding: “Yet again Mrs May will submit herself to ritual humiliation in Brussels.
“The EU is in no mood to negotiate and has dominated our Prime Minister in the talks so far, I expect this meeting to be no different.”
Criticising the UK Government directly, he added: “The British Government has danced to the EU’s tune throughout and it is time to show some steel.”
Mrs May is seeking to confirm to EU leaders the UK Government is making progress on their preferred customs arrangement with the EU following Brexit.
She will also attempt to cover over the deadlock in the Cabinet over whether to pursue a ‘maximum facilitation’ customs model, or a ‘new customs partnership’.