4 For example, the Bank of England Act 1998 states that the objectives of the Bank of England shall be (a) to  maintain price stability, and (b) subject to that, to support the economic policy of Her Majesty’s Government, including its objectives for growth and employment.
The most recent took place in 1997 when a currency board arrangement to the Deutsche Mark was adopted. In 1999, the latter was replaced by the euro. Before the actual accession of Bulgaria into the EU, a Cooperation Agreement was signed by the ECB and the Bulgarian National Bank in January 2005.