A 3-judge bench of Apex Court held as follows regards to default bail u/s 167 CrPC,

From Para 4,

Therefore, the question before us is whether, pending investigation, the petitioner could be kept in custody for a maximum period of 60 days in terms of clause (ii) of proviso (a) to Section 167(2) of the Cr.P.C. or for 90 days in terms of clause (i) of proviso (a) to Section 167(2) of the Cr.P.C. without a charge sheet being filed.

From Para 25,

25. While it is true that merely because a minimum sentence is provided for in the statute it does not mean that only the minimum sentence is imposable. Equally, there is also nothing to suggest that only the maximum sentence is imposable. Either punishment can be imposed and even something in between. Where does one strike a balance? It was held that it is eventually for the court to decide what sentence should be imposed given the range available. Undoubtedly, the Legislature can bind the sentencing court by laying down the minimum sentence (not less than) and it can also lay down the maximum sentence. If the minimum is laid down, the sentencing judge has no option but to give a sentence “not less than” that sentence provided for. Therefore, thewords “not less than” occurring in Clause (i) to proviso (a) of Section 167(2) of the Cr.P.C. (and in other provisions) must be given their natural and obvious meaning which is to say, not below a minimum threshold and in the case of Section 167 of the Cr.P.C. these words must relate to an offence punishable witha minimum of 10 years imprisonment.

From Para 31,

31. In the 154th Report, the Law Commission noted that the unanimous opinion of members of the Bench and the Bar, prosecuting agencies and senior police officers during legal workshops held at various places was that the investigation of serious offences punishable with a sentence of 7 years or more should invariably be undertaken by senior officers. The Law Commission concluded, as a result of these extensive discussions, that it was desirable toseparate the investigating police from the law and order police and as many as seven reasons were given for arriving at this conclusion in Chapter II of the Report.

From Paras 40 and 41,

40. In the present case, it was also argued by learned counsel for the State that the petitioner did not apply for ‘default bail’ on or after 4th January, 2017 till 24th January, 2017 on which date his indefeasible right got extinguished on the filing of the charge sheet. Strictly speaking this is correct since the petitioner applied for regular bail on 11th January, 2017 in the Gauhati High Court – he made no specific application for grant of ‘default bail’. However, the application for regular bail filed by the accused on 11th January, 2017 did advert to the statutory period for filing a charge sheet having expired and that perhaps no charge sheet had in fact being filed. In any event, this issue was argued by learned counsel for the petitioner in the High Court and it was considered but not accepted by the High Court. The High Court did not reject the submission on the ground of maintainability but on merits. Therefore it is not as if the petitioner did not make any application for default bail – such an application was definitely made (if not in writing) then at least orally before the High Court. In our opinion, in matters of personal liberty, we cannot and  should not be too technical and must lean in favour of personal liberty. Consequently, whether the accused makes a written application for ‘default bail’ or an oral application for ‘default bail’ is of no consequence. The concerned court must deal with such an application by considering the statutory requirements namely, whether the statutory period for filing a charge sheet or challan has expired, whether the charge sheet or challan has been filed and whether the accused is prepared to and does furnish bail.
41. We take this view keeping in mind that in matters of personal liberty and Article 21 of the Constitution, it is not always advisable to be formalistic or technical. The history of the personal liberty jurisprudence of this Court and other constitutional courts includes petitions for a writ of habeas corpus and for other writs being entertained even on the basis of a letter addressed to the Chief Justice or the Court.

Then finally in Paras 46 and 47,

46. It was submitted that as of today, a charge sheet having been filed against the petitioner, he is not entitled to ‘default bail’ but must apply for regular bail – the ‘default bail’ chapter being now closed. We cannot agree for the simple reason that we are concerned with the interregnum between 4th January, 2017 and 24th January, 2017 when no charge sheet had been filed, during which period he had availed of his indefeasible right of ‘default bail’. It would have been another matter altogether if the petitioner had not applied for ‘default bail’ for whatever reason during this interregnum. There could be a situation (however rare) where an accused is not prepared to be bailed out perhaps for his personal security since he or she might be facing some threat outside the correction home or for any other reason. But then in such an event, the accused voluntarily gives up the indefeasible right for default bail and having forfeited that right the accused cannot, after the charge sheet or challan has been filed, claim a resuscitation of the indefeasible right. But that is not the case insofar as the petitioner is concerned, since he did not give up his indefeasible right for ‘default bail’ during the interregnum between 4th January, 2017 and 24th January, 2017 as is evident from the decision of the High Court rendered on 11th January, 2017. On the contrary, he had availed of his right to ‘default bail’ which could not have been defeated on 11th January, 2017 and which we are today compelled to acknowledge and enforce.
47. Consequently, we are of opinion that the petitioner had satisfied all the requirements of obtaining ‘default bail’ which is that on 11th January, 2017 he had put in more than 60 days in custody pending investigations into an alleged offence not punishable with imprisonment for a minimum period of 10 years, no charge sheet had been filed against him and he was prepared to furnish bail for his release, as such, he ought to have been released by the High Court on reasonable terms and conditions of bail.

Citations : [2017 SCC ONLINE SC 924], [2017 ALLCC 101 287], [2017 ACR 3 2474], [2017 ALT CRL AP 3 141], [2017 CCR SC 3 371], [2017 DLT 242 79], [2017 ILR KER 3 673], [2017 JLJR 4 37], [2017 KHC 4 470], [2017 KLT 4 284], [2017 MLJ CRL 4 62], [2017 PLJR 4 53], [2017 RCR CRIMINAL 3 996], [2017 SCALE 9 24], [2017 UC 3 1756], [2017 SCC 15 67], [2018 SCC CRI 1 401], [2017 AIR SC 3948], [2017 AIC 178 75], [2018 CRI LJ 155]

Other Sources :

https://indiankanoon.org/doc/194334432/

https://www.casemine.com/judgement/in/599a9dfd4a93262f6c14fba6

https://www.indianemployees.com/judgments/details/rakesh-kumar-paul-versus-state-of-assam