Bills, or acts of parliament are produced that when passed become laws. The laws started in 1066 and have continued forward with many acts modifying a number of earlier ones. There are now far too many laws, many of which have become obsolete but technically still exists. At the current point no one knows what the laws of the country are, and therefore a large amount of time is spent arguing the points in courts. MP's have no training and therefore most have no knowledge of the law, or the effect of their actions.
Many laws are a reaction to some event or publicized circumstance.
In addition MP's raise questions with ministers and other bodies on behalf of constituents and pressure groups. Civil servants conceptually are non political and carry out their wishes, however as they often have more information and better organized many feel they are the power, and many ministers and MP's puppets. The House of Lords Historically a hereditary collection of titled people. Although not truly representative it tends to add common sense. Its organization is quieter and more restrained.