In the United States, federal student loans are consolidated somewhat differently than in the UK, as federal student loans are guaranteed by the U.S. government.

USA
In a federal student loan consolidation, existing loans are purchased and closed by a loan consolidation company or by the Department of Education (depending on what type of federal student loan the borrower holds). Interest rates for the consolidation are based on that year's student loan rate, which is in turn based on the 91-day Treasury bill rate at the last auction in May of each calendar year.

Student loan rates can fluctuate from the current low of 4.70% to a maximum of 8.25% for federal Stafford loans, 9% for PLUS loans. The current consolidation program allows students to consolidate once with a private lender, and reconsolidate again only with the Department of Education. Upon consolidation, a fixed interest rate is set based on the then-current interest rate. Reconsolidating does not change that rate. If the student combines loans of different types and rates into one new consolidation loan, a weighted average calculation will establish the appropriate rate based on the then-current interest rates of the different b being consolidated together.

Federal student loan consolidation is often referred to as refinancing, which is incorrect because the loan rates are not changed, merely locked in. Unlike private sector debt consolidation, student loan consolidation does not incur any fees for the borrower; private companies make money on student loan consolidation by reaping subsidies from the federal government.
Student loan consolidation can be beneficial to students' credit rating, but it's important to note that not all federal student loan consolidation companies report their loans to all credit bureaus.

UK
In the UK Student Loan entitlements are guaranteed, and are recovered using a means-tested system from the student's future income. Student Loans in the UK can not be included in Bankruptcy, but do not affect a person's credit rating because the repayments are recovered from the student's future salary at source by the employer before any income is paid, similar to Income Tax and National Insurance contributions. Many students however, are struggling with debt well after their courses have finished
The level of personal debt in the UK has also risen astonishingly in recent years:
"Total UK personal debt at the end of February 2008 stood at £1,421bn. The growth rate increased to 8.9% for the previous 12 months which equates to an increase of £111bn.

Concerns

In recent years, reports in the media have raised concerns about the use of consolidation loans. The worry is that many people are tempted to consolidate unsecured debt into secured debt, usually secured against their home. Although the monthly payments can often be lower, the total amount repaid is often significantly higher due to the long period of the loan. Debt consolidation sometimes only treats the symptoms of debt and does not address the root problem. In some circumstances, snowballing debt may be a better solution.
There are other alternatives to a debt consolidation loan, where unsecured debt is not "shifted" to secured debt, but is eliminated through a settlement or payment plan. Debt consolidation can be confusing for many people, so it is helpful to learn about all of your options, and sometimes with the help of an advisor.