This statement is true to some degree because of the bicameral nature of the Parliament. The existence of the House of Lords, even with its rather limited powers, is the major example of how the Parliament is in some ways conservative.
For the most part, Parliament functions as a unicameral body. The House of Commons has all of the real power in the Parliament. The House of Commons is directly elected by the people. Therefore, the effective control over the British government is exercised by the people fairly directly.
However, Parliament does still have the House of Lords. The House of Lords cannot do much, but it can hold up bills that it considers to be ill-advised. It cannot prevent them from passing, but it can delay them, forcing the Commons to reconsider. The members of the House of Lords are not elected but are, instead, appointed.
The fact that an unelected body still has some degree of power over the legislative process is shows that there are conservative aspects to an otherwise democratic body.