Unlike other democracies such as the USA the UK constituti...
The executives role is one of administration and enforcement, In the UK the executive consists of the Monarch, the Prime Minister, the governments cabinet members and civil service.
Legislature is responsible for law making this is done by the House of Commons and the House of Lords, however, the House of Lords is less powerful than the House of Commons as it cannot make laws but only delay them. The House of Lords job is scrutinising legislation and suggesting changes before its given royal ascent from the Monarch.
The judiciary is the courts and their job is to apply laws and set precedents in situations where statute is not applicable.
Up until the Constitutional Reform Act 2005 and the inception of the UK Supreme Court, the final court of appeal was the House of Lords. Law Lords playing a part in legislature and judiciary questioned the separation of powers. so to uphold the doctrine of separation of powers CRA1 needed to tackle this issue, this was done by moving law lords to the Supreme Court, making it the final court of appeal for civil and criminal cases except Scottish criminal cases. The aim was to remove legislative functions of the judiciary and show a separation between legislature and the judiciary consequently law Lords who sat in the house of Lords are now justices of the Supreme Court.
However the judiciary is still involved in scrutinising legislation, although senior judges cannot veto legislation they can issue a declaration of incompatibility against proposed legislation under HRA s4  if it goes against any ECHR  articles, this increases judicial independence and separation of powers while maintaining parliamentary sovereignty.
Movement of law Lords to the Supreme Court has made their role less political and less biased allowing judges to scrutinise legislation from a more independent point of view, so in essence the movement from the House of Lords to the Supreme court created a clearer distinction between legislature and judiciary and increased the separation of powers.
The position of Lord Chancellor also went against the doctrine of separation of powers he/she played a part in all three institutions by being a cabinet minister, Lord Speaker and a judge in the House of Lords. Cases such as Pepper v Hart  led to criticism because the Lord Chancellor took part in a decision which involved interpretation of statute he helped create. CRA  aimed to tackle such criticism.
CRA s23(5)  reduced the Lord Chancellors power as head of the judiciary replacing him with a Lord Chief Justice , the Lord Chancellor is also no longer Lord speaker who is now from the House of Lords elected from amongst its members. The Lord Chancellor is now Minister for Justice. Because of these changes the Lord Chancellors job has been spread amongst different people leading to a stronger separation of powers. However, the Lord Chancellor still has a vital role in the judiciary.
CRA s61  reformed judicial appointments by implementing a judicial appointments committee 12 out of 15 of whom are appointed by the Lord Chancellor and the rest by the judges council, the committee is responsible for nominating non supreme court judicial candidates to the Lord Chancellor who can approve or disqualify them, however, he/she cannot choose an alternative . in the case of Supreme Court appointments the Lord Chancellor appoints a committee consisting of the Supreme Court President, Deputy President and appointment committee members of England, Ireland, Scotland and Wales, the committee refers one candidate to the Lord Chancellor who after consideration accepts, rejects or suggests reconsideration, if he accepts he must notify the Prime Minister who makes a recommendation to the Monarch. The role of the Lord Chancellor in judicial appointments undermines judicial independence and shows that the CRA5 hasn’t succeeded in creating a real separation of powers between the executive and judiciary however removal of the Lord Chancellor as Lord Speaker has improved the separation of powers between the executive and legislature.
Section 12 of CRA  is another demonstration of devolution of the Lord Chancellors power. Previously the Lord Chancellor alone held the right to make rules of court however this section has seen the Lord Chief Justice given rights to make court rules, subject to the Lord Chancellors agreement meaning there is a diffusion of power with regards rule making as opposed to a concentration of power in one person which is essentially what the doctrine of separation of powers promotes.
The UK is bound by articles in the ECHR including Article 6  , the right to a fair trial. Without security of tenure this right may be effected an example being the Scottish case of Starrs v Ruxton  where it was said without security of tenure judicial independence or a fair trial isn’t possible. This issue has been addressed in CRA s33  consequently a high court judge can only be removed by a resolution passed by both houses of Parliament. This has increased judicial independence as judges are no longer influenced by fears of losing their job for a decision that doesn’t agree with the executive or legislature.
A key part of CRA  in relation to the separation of powers is s3 which guarantees judicial independence, it has been useful in limiting executive influence over the judiciary because for the first time in legislation, it is stated that ministers and the Lord Chancellor cannot have any influence over judicial decisions this is a step in the right direction in terms of separation of powers between judiciary and the executive and a significant progression from days when the Lord Chancellor was a member of the judicial commission of the House of Lords and the Judicial committee of the Privy Council this section has greatly increased judicial independence compared to what it was in the past.
The guarantee of judicial independence is further emphasised in CRA s17  this section contains the Lord Chancellors oath which makes specific reference to judicial independence... “I will respect the rule of law, defend the independence of the judiciary and discharge my duty to ensure the provision of resources for the efficient and effective support of the courts for which I am responsible".13 Another interesting development since the reform is that the Lord Chancellor does not have to take the judicial Oath anymore this coupled with the Lord Chancellor s oath as outlined in s1713 shows that the Lord Chancellor has been separated from judicial decision making.
Also undermining the UKs separation of powers is the relationship between legislature and executive. in the UK, government which is part of the executive branch is made up of members of the party with a majority in parliament this means it has more power to influence legislation, there is also a problem with the government being able to sit amongst legislature. While law Lords have been separated from legislature via the Supreme Court , CRA  fails to address the executives influence in parliament, pointing to a flaw in the UKs separation of powers. An alternative approach is the USAs structure where the President is elected separately from congress.
On the other hand judicial review is an excellent example of courts being able to prevent abuse of power by the executive. The system allows courts to ensure the executive is acting within the law created by legislature this is a great demonstration of separation of powers being effective and government being equal under the rule of law.
All things considered since the CRA  has come into effect the introduction of the new Supreme Court has increased separation of powers between judiciary and legislature as it has removed law Lords from political debate and made the judiciary more independent however the UK is still a long way from achieving a real separation of powers because the executive still plays a big part in the judiciary with the Lord Chancellors involvement in judicial appointments. Another area that seems to violate the doctrine of separation of powers is the relationship between the government and legislature once these issues are resolved we might be able to say that the UK has a real separation of powers.