Mrs Merkel has formed an alliance to let Brexit happen on her terms
The paper seen by the Bild newspaper says Germany – the powerhouse of the European Union and the biggest payer into its treasury – will reject "all forms of individual agreements because this could lead to a split in the 27 EU states."
She wants the 24 month time frame allotted to the talks on Britain’s terms for leaving to be cut to 15 months "due to the necessary involvement of the European Parliament and of the forthcoming EP election campaign."
Mrs Merkel, who is seeking a fourth term in power in the German general election slated for September, says all "contentious issues" – such as the free movement of people across EU borders – must be negotiated now and not left to some nebulous undecided future date.
Bild report that Merkel will reject all forms of individual agreements as it could split up the EU
Today is the start of the negotiations which last for two years. Everything remains the same at first
But she recognises that "future relations" with London, which include the status of students, financial concordats and the movement of goods, could take far longer to crystallise and believes that the EU Commission prediction of talks on these matters taking up to ten years a real possibility.
Germany, says the paper, highlights 60 sectors of its economy which will be affected by Brexit. It speaks of a general "uncertainty" abroad "due to the break up of the internal market."
Since October last year German ministries have been collecting data on the sectors – among them manufacturing and financial – that will be hit by Brexit.
Mrs May signed the letter requesting the EU for permission to leave last night
Mrs Merkel has appointed former eurocrat Uwe Corsepius, 56, as her point man in the ministry to handle all German concerns during Brexit talks. He is a close confidant of the chancellor but viewed by his erstwhile colleagues in Brussels as a "gruff" and humourless apparatchik more interested in bottom lines than people.
German economics minister Brigitte Zypries said on the morning of Brexit; "Today is the start of the negotiations which last for two years. Everything remains the same at first.
"The rights and obligations of EU membership continue to apply the the United Kingdom. A new cooperation agreement between the EU and the United Kingdom should be completed after the withdrawal negotiations. There is no blueprint, but both sides have an interest in a close partnership, because trade barriers take advantage of no-one.
Germany have highlighted 60 sectors of its economy which will be affected by Brexit Brexit day LIVE: images from around the country as Britain invokes Article 50 Wed, March 29, 2017
The country reacts as Theresa May officially invokes Article 50, and begins the process of Britain leaving the European Union
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The official photo made available by 10 Downing Street
"Whether and what consequences Brexit will have in the long term depends very much on the future partnership. It makes sense to have clarity, because uncertainty always slows investment.
"I'm not worried because the German economy is robust and internationally intertwined. Britain faces much greater risks than the EU."