Jacob Rees-Mogg, the leader of the pro-Brexit European Research Group (ERG) affects the sterling vs euro interbank exchange rate in the following way. 

Michel Barnier is the European Union's (EU) Chief Brexit Negotiator. When Mr. Barnier has suggested that a Brexit deal looks nearer, the value of sterling has often risen.

Article 50 gives any member state of the EU the right to exit unilaterally. The article allows for 2 years to negotiate this exit.

The relationship between Brexit and the currency exchange rate so far has been that, the closer the UK looks to agreeing a deal with the EU, the further the pound strengthens.

The pound interbank exchange rate rose against the euro, US dollar and Australian dollar in February! This is primarily because it now looks much less likely that the UK will crash out of the EU.

Sterling gained in January, as Parliament took on a larger role in Brexit. This is leading investors to hope that the UK retains ties with the EU.

The pound has strengthened, first because UK unemployment held steady at 4.0% in December, said the Office for National Statistics

The pound held its ground last week, first because the UK services sector unexpectedly slowed.

Sterling goes up, up and away versus the common currency! The pound to euro interbank exchange rate soared by +3 cents this week, at one point above 1.16, its highest since May 2017.The pound wore rocket boosters this week, because it looks likely that the UK will avoid a 'No Deal' Brexit.

Sterling has weakened, as the Bank of England warned at its latest interest rate decision that "Brexit uncertainties have intensified considerably since the [BoE's] last meeting."