Theresa May’s letter to Donald Tusk triggering article 50 (Report, 30 March) makes disturbing references to future co-operation with the EU on fighting crime and terrorism. Specifically, she implies that the willingness of the UK government to continue to cooperate fully with the EU on security will be dependent on whether a satisfactory deal can be done on future trading arrangements and other matters post-Brexit.

What she says, in short, is that she is willing to put people’s lives at risk in order to achieve a good deal. In effect, she is trying to use the safety of both UK and EU citizens as a bargaining chip. It seems to me that somewhere in all this Brexit madness the government has lost its moral compass.

Playing fast and loose with people’s lives is irresponsible, and threatening to reduce co-operation with the EU on security should have no place in the Brexit negotiations.

Michael Hardwick

Manaton, Devon

• Any implied threat to use the UK’s security strength as a bargaining chip in Brexit negotiations might be bad politics for the self-serving functionaries of the European parliament (EU warns: don’t blackmail us, 30 March), but the realpolitik is that the economic settlement will be unavoidably linked with security cooperation for decades to come. A bad economic Brexit settlement will cause the UK to focus on narrower national self-interest and reduced expenditure on European security will be inevitable eventually. This process will be driven by financial pressure resulting from the bad settlement and political pressure from whichever political parties make this a campaigning issue. It’s called democracy. Have the Eurocrats learned nothing from the Brexit shambles?

Dr John Birtill

Guisborough, North Yorkshire

• Join the debate – email guardian.letters@theguardian.com

• Read more Guardian letters – click here to visit gu.com/letters