5.  The applicant was born in 1952 and lives in Celje. 6.  He had been a professional truck driver until he became unable to work due to epilepsy. 7.  On 29 September 2003 the applicant was certified as having a “category III work-related disability” as a result of his condition. He was found to have a right to be reassigned to a suitable position of employment where he and others would not be at risk because of his condition, with (retroactive) effect from 14 August 2002. 8.  On 21 February 2005 the Celje regional unit of the Pension and Disability Insurance Institute of Slovenia (hereinafter “the regional ZPIZ”) granted the applicant a so-called “allowance for the period of waiting to be reassigned to or employed in a different appropriate position of employment” (hereinafter “waiting period allowance”) from 8 October 2004. Though the sums appear to be lower during the first few months, he had been subsequently receiving around 390 euros (EUR) per month in waiting period allowance. The regional ZPIZ relied on section 123 of the Pension and Disability Insurance Act (hereinafter “the 1992 Act”) and section 446 of the new Pension and Disability Insurance Act (hereinafter “the 1999 Act” – see paragraphs 24 and 25 below). It noted that the applicant had been registered as unemployed on 3 March 2003 and had been a beneficiary under section 22 of the 1999 Act from 1 March 2003 to 7 October 2004. Thus, once his unemployment allowance had come to an end he had become entitled to a waiting period allowance under section 123 of the 1992 Act (see paragraph 24 below). The regional ZPIZ also noted that, under section 193 of the 1992 Act, beneficiaries were entitled to a waiting period allowance until they fulfilled the conditions for retirement (ibid.). 9.  On 15 October 2010 the applicant’s doctor informed the regional ZPIZ about a shoulder injury the applicant had sustained and requested a reassessment of his level of disability. 10.  On the basis of, inter alia, information provided by the applicant’s doctor, the regional ZPIZ, on 2 February 2011, decided that the applicant had a right to be reassigned to another position of employment with several limitations, such as not to work at unprotected heights or drive category C and E vehicles, with effect from 1 February 2011. Subsequently, on 28 June 2011 it adopted a decision granting him a disability allowance (nadomestilo za invalidnost) from 24 February 2011 onwards. The regional ZPIZ relied on the 1999 Act, which had introduced certain new disability benefits (the term “disability benefit” is used to cover any type of allowance that arises from a disability) and discontinued some of those provided for under the 1992 Act, including the waiting period allowance. Sections 397 and 446 of the 1999 Act stipulated that a right to a disability allowance applied as from 1 January 2003 (see paragraph 25 below). The regional ZPIZ noted in its decision that the applicant had not been insured under the compulsory insurance scheme at the onset of his disability, but had been registered as unemployed on 3 March 2003 within thirty days of the final decision on his disability, as required by section 97 of the 1999 Act. It was established that his capacity to work had in fact further reduced, even though the category (III) of his disability remained unchanged. The regional ZPIZ found that, pursuant to section 94(1)(1) and (3)(1) of the 1999 Act, he should receive a benefit in the form of disability allowance, which in his case amounted to EUR 192.91. It drew the applicant’s attention to section 185 of the 1999 Act, which required beneficiaries to inform the ZPIZ of any change in circumstances which could affect their rights under that Act (see paragraph 26 below). 11.  On 21 July 2011 the applicant appealed against the above decision, arguing that in determining the amount of his disability benefit, the regional ZPIZ should have respected the principle of acquired rights. He pointed out that his benefit had reduced considerably, even though his disability had in fact worsened, and claimed that such a decision was unlawful. 12.  On 21 October 2011 the central Pension and Disability Insurance Institute of Slovenia (hereinafter “the central ZPIZ”) dismissed the applicant’s appeal, confirming that the regional ZPIZ had properly applied the law and correctly calculated the amount of his disability allowance. 13.  On 5 December 2011 the applicant lodged a claim with the Celje Labour and Social Court challenging the above decisions. He reiterated that the disability allowance granted to him under the 1999 Act violated his acquired rights and that instead of increasing his benefit it reduced it by half, which was unlawful and unconstitutional. 14.  On 26 March 2012 the Celje Labour and Social Court dismissed the applicant’s claim. It explained that while recipients of disability-related rights under the 1992 Act retained their acquired rights after the date set out in section 446 of the 1999 Act, in the applicant’s case a reassessment of his disability had been carried out on 2 February 2011 due to a worsening of his condition (see paragraph 10 above), which had resulted in further workplace limitations and his rights being consequently determined anew. In cases where a fresh assessment was made the 1999 Act was to be applied. The court concluded that the 1999 Act did not contain the right to a waiting period allowance. Instead, under section 94, it provided for the disability allowance (see paragraph 25 below) which had been correctly granted to the applicant. 15.  On 25 April 2012 the applicant appealed against the judgment, repeating the complaints he had made before the first-instance court and alleging that he ought to have been informed of the consequences of a request for a reassessment of his disability. If that had been the case, he would have “forbidden” his doctor from making such a request. Lastly, he reiterated that the decision of the regional ZPIZ of 28 June 2011 (see paragraph 10 above) was unlawful and unconstitutional, as it violated his right to social security; he pointed out that he was unable to survive on the newly determined disability allowance. 16.  On 21 June 2012 the Higher Labour and Social Court dismissed the applicant’s appeal, confirming the position of the lower court that the applicant’s case concerned a change in the level of disability, which had required a fresh determination of his disability benefit. In such a situation, section 397(3) of the 1999 Act provided that the applicant acquired rights under the Act. Also, since the applicant’s rights had been determined anew, the Higher Labour and Social Court concluded that there had been no violation of his acquired rights related to social security, and thus no violation of the Constitution. 17.  On 4 September 2012 the applicant lodged an appeal on points of law before the Supreme Court, arguing that he could not have legitimately expected that the worsening of his disability would result in a severe reduction of his disability benefit. In that connection, he alleged that the Higher Labour and Social Court’s view that the reduction did not interfere with his acquired rights or constitute a violation of his constitutional right to social security was arbitrary, as the court had provided no reasoning for that conclusion. The applicant further alleged that the newly determined amount of disability benefit interfered with his constitutional right to property. 18.  On 5 March 2013 the Supreme Court dismissed the applicant’s appeal on points of law, finding that the Higher Labour and Social Court had sufficiently explained that the change in his level of disability had required a fresh determination of his benefit in accordance with the 1999 Act. 19.  On 21 May 2013 the applicant lodged a constitutional complaint against the Supreme Court’s judgment, alleging a violation of his constitutional rights to property and social security. He argued that the reduction in the disability benefit had put his subsistence at risk and failed the test of proportionality. 20.  On 18 November 2013 the Constitutional Court refused to accept the applicant’s complaint for consideration on the merits, referring to section 55b(2) of the Constitutional Court Act (see paragraph 27 below). 21.  In the meantime, on 22 May 2013, the applicant fulfilled the conditions for a retirement pension in the amount of EUR 374.73 and his disability allowance was discontinued from that date. He thus received the disability allowance for a period of twenty-seven months. 22.  Data concerning the applicant’s income provided by the Slovenian tax authorities shows that he received EUR 4,908 in 2010 in pension and disability insurance and, after the impugned change in his allowance, EUR 2,902 in 2011 and EUR 2,480 in 2012.